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Build your own math worksheets from 30,000+ problems for grades 3 to 12, from fractions to AP Calculus. Every problem comes with step-by-step solutions.

Add and subtract fractions with like denominators

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5544214
Find the sum: \(\frac{2}{10}+\frac{5}{10}\).

Hints

- Both fractions already use the same-sized parts. - Combine the counts of tenths without changing the part size.

Solution

1. Both fractions use tenths, so the parts are the same size. 2. Add the numerators and keep the denominator: \(\frac{2+5}{10}=\frac{7}{10}\).

Answer

\(\frac{7}{10}\)
5544224
The blue and orange parts of the bar represent two addends in tenths. a) Write the two addends. b) Find their sum.
Figure for problem 554422

Hints

- Count the tenths represented by each color separately. - The two colors use equal-sized parts, so combine their counts.

Solution

1. The blue part covers \(\frac{2}{10}\), and the orange part covers \(\frac{3}{10}\). 2. Together they cover \(\frac{2}{10}+\frac{3}{10}=\frac{5}{10}\).

Answer

a) \(\frac{2}{10}\) and \(\frac{3}{10}\) b) \(\frac{5}{10}\)
5106104
Calculate each expression. Write each answer in simplest form. a) \(\frac{7}{12}+\frac{2}{12}+\frac{1}{12}\) b) \(\frac{9}{10}-\frac{3}{10}+\frac{2}{10}\) c) \(\frac{7}{8}+\frac{3}{8}-\frac{4}{8}\)

Hints

- In each expression, the fractions already use equal-sized parts. - Combine the numerators while keeping the common denominator. - After evaluating, check whether the resulting numerator and denominator share a common factor.

Solution

1. For a), the denominator stays \(12\): \(\frac{7+2+1}{12}=\frac{10}{12}=\frac{5}{6}\). 2. For b), the denominator stays \(10\): \(\frac{9-3+2}{10}=\frac{8}{10}=\frac{4}{5}\). 3. For c), the denominator stays \(8\): \(\frac{7+3-4}{8}=\frac{6}{8}=\frac{3}{4}\).

Answer

a) \(\frac{5}{6}\) b) \(\frac{4}{5}\) c) \(\frac{3}{4}\)
5107064
A dotted quarter note has the time value of three eighth notes, or \(\frac{3}{8}\) of a whole note. A musician wants to fill \(\frac{3}{4}\) of a whole-note time and has already written one dotted quarter note. How many eighth notes, each worth \(\frac{1}{8}\), are needed to complete the amount exactly?

Hints

- Rename the target amount using eighths. - Compare the target number of eighth-sized parts with the amount already used. - Each additional note contributes one eighth-sized part.

Solution

1. Rename the target in eighths: \(\frac{3}{4}=\frac{6}{8}\). 2. The dotted quarter note uses \(\frac{3}{8}\), so the remaining amount is \(\frac{6}{8}-\frac{3}{8}=\frac{3}{8}\). 3. Each eighth note is \(\frac{1}{8}\), so three eighth notes fill the remaining \(\frac{3}{8}\).

Answer

\(3\) eighth notes
5405954
A marker starts at \(\frac{5}{6}\), moves two sixth-sized steps forward, and then moves three sixth-sized steps back. Write a like-denominator addition-and-subtraction equation for the moves. Where does the marker finish? Give the final position in sixths.

Hints

- A forward move adds sixths; a backward move subtracts sixths. - All fractions already have the same denominator. - Keep the final position in sixths, as requested.

Solution

1. Represent the forward move by addition and the backward move by subtraction: \(\frac{5}{6}+\frac{2}{6}-\frac{3}{6}\). 2. Add first: \(\frac{5}{6}+\frac{2}{6}=\frac{7}{6}\). 3. Then subtract: \(\frac{7}{6}-\frac{3}{6}=\frac{4}{6}\). 4. Therefore, the marker finishes at \(\frac{4}{6}\).

Answer

\(\frac{5}{6}+\frac{2}{6}-\frac{3}{6}=\frac{4}{6}\)
5406124
Use \(\frac{3}{4}\), \(\frac{1}{4}\), and \(1\) to write two addition equations and two subtraction equations in the same fact family.

Hints

- Identify the two parts and the whole. - Addition combines the parts. - Subtraction starts with the whole and removes one part.

Solution

1. The parts combine to the whole: \(\frac{3}{4}+\frac{1}{4}=1\). 2. Reversing the addends gives \(\frac{1}{4}+\frac{3}{4}=1\). 3. Subtracting either part from the whole gives the other part: \(1-\frac{3}{4}=\frac{1}{4}\) and \(1-\frac{1}{4}=\frac{3}{4}\).

Answer

\(\frac{3}{4}+\frac{1}{4}=1\) \(\frac{1}{4}+\frac{3}{4}=1\) \(1-\frac{3}{4}=\frac{1}{4}\) \(1-\frac{1}{4}=\frac{3}{4}\)
5406154
Compare \(\frac{11}{12}-\frac{5}{12}\) and \(\frac{2}{12}+\frac{3}{12}\). a) Which expression has the greater value? b) What is the difference between their values?

Hints

- Evaluate each expression before comparing them. - Keep twelfths as the common unit. - For part b), subtract the smaller result from the larger result.

Solution

1. The subtraction expression equals \(\frac{11}{12}-\frac{5}{12}=\frac{6}{12}\). 2. The addition expression equals \(\frac{2}{12}+\frac{3}{12}=\frac{5}{12}\). 3. Since \(\frac{6}{12}>\frac{5}{12}\), the subtraction expression is greater. 4. The difference is \(\frac{6}{12}-\frac{5}{12}=\frac{1}{12}\).

Answer

a) \(\frac{11}{12}-\frac{5}{12}\) b) \(\frac{1}{12}\)
5406174
Evaluate \(\frac{1}{8}+\frac{3}{8}+\frac{2}{8}\) in two ways. a) First add the first two fractions. b) First add the last two fractions. c) Do both groupings give the same result?

Hints

- Keep the denominator fixed while adding eighths. - Follow each requested grouping separately. - Compare the two totals before answering part c).

Solution

1. For part a), \(\left(\frac{1}{8}+\frac{3}{8}\right)+\frac{2}{8}=\frac{4}{8}+\frac{2}{8}=\frac{6}{8}\). 2. For part b), \(\frac{1}{8}+\left(\frac{3}{8}+\frac{2}{8}\right)=\frac{1}{8}+\frac{5}{8}=\frac{6}{8}\). 3. Both groupings give \(\frac{6}{8}\), so they have the same result.

Answer

a) \(\frac{6}{8}\) b) \(\frac{6}{8}\) c) Yes.
5406184
Evaluate these expressions and order their results from least to greatest: A. \(\frac{7}{10}-\frac{2}{10}\) B. \(\frac{3}{10}+\frac{4}{10}\) C. \(\frac{9}{10}-\frac{1}{10}\)

Hints

- Find each result before comparing. - Keep all results in tenths. - Match the ordered fractions back to their letters.

Solution

1. A equals \(\frac{5}{10}\). 2. B equals \(\frac{7}{10}\). 3. C equals \(\frac{8}{10}\). 4. Since \(5<7<8\), the order from least to greatest is A, B, C.

Answer

A = \(\frac{5}{10}\), B = \(\frac{7}{10}\), C = \(\frac{8}{10}\); least to greatest: A, B, C.
5407404
Without first finding both complete sums, compare \(\frac{3}{12}+\frac{5}{12}\) and \(\frac{3}{12}+\frac{4}{12}\). Which expression is greater, and by how much? Explain how the shared addend helps.

Hints

- Identify the addend that is the same in both expressions. - Compare only the addends that differ. - Adding the same amount to two numbers preserves the difference between them.

Solution

1. Both expressions contain the same addend, \(\frac{3}{12}\). 2. The other addends are \(\frac{5}{12}\) and \(\frac{4}{12}\). Since \(\frac{5}{12}\) is \(\frac{1}{12}\) greater, the first complete sum is also \(\frac{1}{12}\) greater. 3. Checking gives \(\frac{8}{12}\) and \(\frac{7}{12}\), whose difference is \(\frac{1}{12}\).

Answer

\(\frac{3}{12}+\frac{5}{12}\) is greater by \(\frac{1}{12}\).
5407434
Cards A–D show four different fractions made from eighths. Choose two different cards whose sum is less than \(1\) but as great as possible. Which cards should be chosen, and what is the sum?
Figure for problem 540743

Hints

- Read each card's shaded fraction from the model. - Start by considering the largest card values. - Check that your chosen sum stays below one whole.

Solution

1. The cards show A \(=\frac{1}{8}\), B \(=\frac{2}{8}\), C \(=\frac{3}{8}\), and D \(=\frac{4}{8}\). 2. To make the greatest sum with two different cards, start with the two largest values, C and D. 3. Their sum is \(\frac{3}{8}+\frac{4}{8}=\frac{7}{8}\), which is less than \(1\). 4. Any other pair replaces one of these cards with a smaller value, so no other allowed pair can have a greater sum.

Answer

Cards C and D; \(\frac{7}{8}\)
5407504
A ribbon is \(\frac{11}{12}\) yard long. Cards A–E show five possible lengths. Maya cuts off one card's length so that exactly \(\frac{1}{2}\) yard remains. Which card should she use?
Figure for problem 540750

Hints

- First determine how much must be removed from the ribbon. - Rename the remaining half yard in twelfths. - Match the required cut length to one of the visual cards.

Solution

1. The amount to cut off is \(\frac{11}{12}-\frac{1}{2}\). 2. Rename \(\frac{1}{2}\) as \(\frac{6}{12}\). The cut length must be \(\frac{5}{12}\) yard. 3. Reading the models, card E represents \(\frac{5}{12}\), so card E is the correct choice.

Answer

Card E
5544234
Find the missing numerator: \(\frac{\square}{8}+\frac{3}{8}=\frac{7}{8}\).

Hints

- All three fractions use eighth-sized parts. - Think of the equation as a missing-addend fact using the numerators. - Determine how many more eighths are needed to reach the target.

Solution

1. The missing eighths and \(3\) eighths must total \(7\) eighths. 2. The missing number of eighths is \(7-3=4\). 3. Therefore, the missing fraction is \(\frac{4}{8}\).

Answer

\(4\)
5317424
Two ribbons, \(D\) and \(E\), are shown on equally scaled number lines. Each interval between whole numbers is divided into eighths. a) Find the length of ribbon \(D\). b) Find the length of ribbon \(E\). c) Which ribbon is longer, and by how much? d) Find the total length of both ribbons.
Figure for problem 531742

Hints

- Each small step represents \(\frac{1}{8}\). - Subtract the starting value from the ending value for each ribbon. - Use eighths to compare, subtract, and add the lengths.

Solution

1. Ribbon \(D\) runs from \(\frac{2}{8}\) to \(\frac{11}{8}\), so its length is \(\frac{11}{8}-\frac{2}{8}=\frac{9}{8}=1\frac{1}{8}\). 2. Ribbon \(E\) runs from \(\frac{5}{8}\) to \(\frac{15}{8}\), so its length is \(\frac{15}{8}-\frac{5}{8}=\frac{10}{8}=\frac{5}{4}=1\frac{1}{4}\). 3. Since \(1\frac{1}{4}=1\frac{2}{8}\), ribbon \(E\) is longer by \(\frac{1}{8}\). 4. The total length is \(1\frac{1}{8}+1\frac{1}{4}=1\frac{1}{8}+1\frac{2}{8}=2\frac{3}{8}\).

Answer

a) \(1\frac{1}{8}\) b) \(1\frac{1}{4}\) c) Ribbon \(E\) is longer by \(\frac{1}{8}\). d) \(2\frac{3}{8}\)
5317694
Points \(A\) and \(B\) are marked on the number line. a) What values are marked by \(A\) and \(B\)? b) Find the distance between the points. Write the result as a fraction in simplest form or as a mixed number.
Figure for problem 531769

Hints

- Count the equal intervals between consecutive whole numbers. - Read each point by counting steps from \(0\). - Subtract the smaller value from the larger value to find the distance.

Solution

1. Each interval between whole numbers is divided into thirds, so one step is \(\frac{1}{3}\). 2. Point \(A\) is at \(\frac{2}{3}\), and point \(B\) is at \(2\frac{1}{3}=\frac{7}{3}\). 3. The distance is \(\frac{7}{3}-\frac{2}{3}=\frac{5}{3}=1\frac{2}{3}\).

Answer

a) \(A=\frac{2}{3}\), \(B=2\frac{1}{3}\) b) \(1\frac{2}{3}\)
5406114
Kai writes \(1\frac{3}{5}+\frac{2}{5}=1\frac{5}{10}\). Explain Kai's error and give the correct sum.

Hints

- Identify the size of the fractional parts being combined. - When equal-sized parts are added, does the size of each part change? - Check whether the fractional pieces complete another whole.

Solution

1. The fractional parts are both fifths, so their denominators stay \(5\) when they are added. 2. \(\frac{3}{5}+\frac{2}{5}=\frac{5}{5}=1\). 3. Therefore, \(1\frac{3}{5}+\frac{2}{5}=2\). Kai incorrectly added the denominators as well as the numerators.

Answer

Kai should keep the denominator \(5\). The correct sum is \(2\).
5406134
Find every way to add two positive fractions with denominator \(8\) to make \(1\). List each pair only once, with the smaller numerator first.

Hints

- Rewrite one whole using eighths. - Think about pairs of positive whole-number numerators that make the numerator of one whole. - Stop when listing a new pair would only reverse one you already have.

Solution

1. One whole is \(\frac{8}{8}\), so the two numerators must add to \(8\). 2. Starting with numerator \(1\) gives \(\frac{1}{8}+\frac{7}{8}=1\). 3. Continuing without reversing a pair gives \(\frac{2}{8}+\frac{6}{8}=1\), \(\frac{3}{8}+\frac{5}{8}=1\), and \(\frac{4}{8}+\frac{4}{8}=1\). 4. Any larger first numerator would only reverse a pair already listed.

Answer

\(\frac{1}{8}+\frac{7}{8}=1\), \(\frac{2}{8}+\frac{6}{8}=1\), \(\frac{3}{8}+\frac{5}{8}=1\), \(\frac{4}{8}+\frac{4}{8}=1\)
5406144
Priya writes \(2\frac{1}{5}-\frac{3}{5}=2\frac{2}{5}\). Explain Priya's mistake and find the correct difference.

Hints

- Compare the fractional part of the mixed number with the fraction being subtracted. - If the fractional part is too small, rename one whole using fifths. - After regrouping, subtract equal-sized fifths.

Solution

1. The fractional part \(\frac{1}{5}\) is smaller than \(\frac{3}{5}\), so one whole must be regrouped before subtracting. 2. Rename \(2\frac{1}{5}\) as \(1\frac{6}{5}\). 3. Then \(1\frac{6}{5}-\frac{3}{5}=1\frac{3}{5}\). 4. Priya subtracted the fractional parts as though \(\frac{1}{5}\) were large enough, without regrouping a whole.

Answer

Priya needed to regroup one whole. The correct difference is \(1\frac{3}{5}\).
5406164
Two equal fractions add to \(1\frac{2}{10}\). Each fraction has denominator \(10\). What is each fraction?

Hints

- Express the mixed-number total entirely in tenths. - Equal addends receive the same number of tenths. - Keep denominator \(10\), as required by the problem.

Solution

1. Rewrite the total as \(\frac{12}{10}\). 2. Split the twelve tenths equally between the two addends: \(12\div2=6\). 3. Each fraction is \(\frac{6}{10}\), which is equivalent to \(\frac{3}{5}\).

Answer

\(\frac{6}{10}\)
5406194
A blue ribbon is \(2\frac{1}{4}\,\text{m}\) long. Maya adds a second ribbon so the total length is \(3\frac{1}{2}\,\text{m}\). How long is the second ribbon?

Hints

- The second ribbon is the total length minus the first ribbon’s length. - Rewrite the half as fourths before subtracting. - Include meters with the final mixed-number length.

Solution

1. Express both lengths in fourths: \(2\frac{1}{4}=\frac{9}{4}\) and \(3\frac{1}{2}=\frac{14}{4}\). 2. Subtract the original ribbon from the total length: \(\frac{14}{4}-\frac{9}{4}=\frac{5}{4}\). 3. Convert the result to a mixed number: \(\frac{5}{4}=1\frac{1}{4}\).

Answer

\(1\frac{1}{4}\,\text{m}\)
5406204
Marisol fills the boxes in \(\frac{8}{12}\;\square\;\frac{3}{12}\;\square\;\frac{2}{12}=\frac{7}{12}\) with \(+\) and then \(-\). Test her choice. If it is wrong, give the correct pair of signs.

Hints

- Evaluate the student’s proposed signs before trying a replacement. - Compare the proposed result with the target numerator. - Test the other sign order from left to right.

Solution

1. Marisol’s choice gives \(\frac{8}{12}+\frac{3}{12}-\frac{2}{12}=\frac{9}{12}\), not \(\frac{7}{12}\). 2. Using subtraction first gives \(\frac{8}{12}-\frac{3}{12}=\frac{5}{12}\). 3. Adding \(\frac{2}{12}\) next gives \(\frac{5}{12}+\frac{2}{12}=\frac{7}{12}\). 4. The correct signs are \(-\) and then \(+\).

Answer

Marisol’s choice is wrong. The correct equation is \(\frac{8}{12}-\frac{3}{12}+\frac{2}{12}=\frac{7}{12}\).
5406214
Find \(n\): \(\frac{n}{12}+\frac{7}{12}-\frac{2}{12}=1\).

Hints

- Simplify the known addition-subtraction part first. - Rewrite one whole in twelfths. - Find the numerator needed to complete the whole.

Solution

1. Combine the known terms: \(\frac{7}{12}-\frac{2}{12}=\frac{5}{12}\). 2. One whole is \(\frac{12}{12}\), so the missing amount is \(\frac{12}{12}-\frac{5}{12}=\frac{7}{12}\). 3. Therefore, \(n=7\).

Answer

\(n=7\)
5407424
The two models show two fractions made from eighth-sized parts. a) Find the two fractions and their sum. b) Explain why the sum has eighth-sized parts rather than sixteenth-sized parts. c) State a rule in words for adding any two fractions that both have denominator \(8\).
Figure for problem 540742

Hints

- Read how many of the eight equal parts are shaded in each model. - Ask whether combining pieces changes the size of each individual piece. - Describe what changes and what stays the same in the fraction notation.

Solution

1. The first model shows \(\frac{3}{8}\), and the second shows \(\frac{2}{8}\). 2. Together they contain five eighth-sized parts, so \(\frac{3}{8}+\frac{2}{8}=\frac{5}{8}\). 3. Adding the fractions combines counts of the same-sized eighths; it does not cut each eighth into smaller parts. 4. Therefore, when two fractions have denominator \(8\), add their numerators and keep denominator \(8\).

Answer

a) \(\frac{3}{8}+\frac{2}{8}=\frac{5}{8}\) b) The pieces are already equal-sized eighths, so adding combines their counts without changing their size. c) Add the numerators and keep denominator \(8\).
5407444
Model S shows a starting amount. Cards A–C show three amounts that may be subtracted. Subtract exactly one card from the starting amount. a) Find every possible result and write each result in eighths. b) Order the distinct results from least to greatest. c) Describe how the result changes as the subtracted card increases.
Figure for problem 540744

Hints

- Read the starting amount and each card amount from the eighths models. - Subtract one card at a time from the same starting fraction. - Compare how the endpoints change as the card amount gets larger.

Solution

1. Model S shows \(\frac{5}{8}\). Cards A, B, and C show \(\frac{1}{8}\), \(\frac{2}{8}\), and \(\frac{3}{8}\). 2. The possible results are \(\frac{5}{8}-\frac{1}{8}=\frac{4}{8}\), \(\frac{5}{8}-\frac{2}{8}=\frac{3}{8}\), and \(\frac{5}{8}-\frac{3}{8}=\frac{2}{8}\). 3. From least to greatest, the results are \(\frac{2}{8},\frac{3}{8},\frac{4}{8}\). 4. As the amount subtracted increases by \(\frac{1}{8}\), the result decreases by \(\frac{1}{8}\).

Answer

a) A: \(\frac{4}{8}\); B: \(\frac{3}{8}\); C: \(\frac{2}{8}\) b) \(\frac{2}{8}<\frac{3}{8}<\frac{4}{8}\) c) Each increase of \(\frac{1}{8}\) in the subtracted amount decreases the result by \(\frac{1}{8}\).
5407454
Use models A and B to add the two amounts. First use part of model B to complete the next whole shown by model A. Show how you decompose the second addend and state the final mixed number.
Figure for problem 540745

Hints

- Read both addends from the two models. - Determine how many eighths model A needs to complete its next whole. - Split model B into the amount needed for that whole and the amount left over.

Solution

1. Model A shows \(1\frac{5}{8}\), and model B shows \(\frac{6}{8}\). 2. Model A needs \(\frac{3}{8}\) to reach \(2\), so decompose \(\frac{6}{8}\) as \(\frac{3}{8}+\frac{3}{8}\). 3. Then \(1\frac{5}{8}+\frac{3}{8}=2\), with \(\frac{3}{8}\) left. 4. The final sum is \(2\frac{3}{8}\).

Answer

\(\frac{6}{8}=\frac{3}{8}+\frac{3}{8}\), so the sum is \(2\frac{3}{8}\).
5407464
Compare \(2\frac{7}{10}+\frac{6}{10}\) with \(2\frac{8}{10}+\frac{5}{10}\). Explain why moving \(\frac{1}{10}\) from the second addend to the first preserves the sum, then find the common value.

Hints

- Compare how each addend changes from the first expression to the second. - Equal increases and decreases leave a total unchanged. - Use the expression that is easier to combine after recognizing the equality.

Solution

1. The first addend increases by \(\frac{1}{10}\), while the second addend decreases by \(\frac{1}{10}\). 2. These opposite changes cancel, so the two sums are equal. 3. Compute either sum: \(2\frac{8}{10}+\frac{5}{10}=2\frac{13}{10}=3\frac{3}{10}\).

Answer

The sums are equal because one addend increases by \(\frac{1}{10}\) while the other decreases by \(\frac{1}{10}\). Each sum is \(3\frac{3}{10}\).
5407474
Use the number line to find \(3\frac{2}{8}-1\frac{7}{8}\) by counting up from the smaller number to the larger number. Break the count into a jump to \(2\), a jump to \(3\), and a final fractional jump.
Figure for problem 540747

Hints

- Treat subtraction as the distance from the smaller marked value to the larger one. - Use the labeled whole-number landmarks to organize the count. - Add the three jump lengths at the end.

Solution

1. From \(1\frac{7}{8}\) to \(2\) is \(\frac{1}{8}\). 2. From \(2\) to \(3\) is \(1\). 3. From \(3\) to \(3\frac{2}{8}\) is \(\frac{2}{8}\). 4. The total difference is \(\frac{1}{8}+1+\frac{2}{8}=1\frac{3}{8}\).

Answer

\(\frac{1}{8}+1+\frac{2}{8}=1\frac{3}{8}\), so \(3\frac{2}{8}-1\frac{7}{8}=1\frac{3}{8}\).
5407484
Use models A and B to find the difference between the two amounts in two ways: a) regroup one whole in the larger amount; b) rewrite the larger mixed number as an improper fraction. Show that the methods produce the same result.
Figure for problem 540748

Hints

- Read the two quantities from models A and B. - For regrouping, trade one whole for sixth-sized parts. - For the improper-fraction method, count how many sixths are in the entire mixed number.

Solution

1. Model A shows \(2\frac{1}{6}\), and model B shows \(\frac{5}{6}\). 2. For method a), regroup \(2\frac{1}{6}\) as \(1\frac{7}{6}\). Then \(1\frac{7}{6}-\frac{5}{6}=1\frac{2}{6}=1\frac{1}{3}\). 3. For method b), rewrite \(2\frac{1}{6}=\frac{13}{6}\). Then \(\frac{13}{6}-\frac{5}{6}=\frac{8}{6}=1\frac{2}{6}=1\frac{1}{3}\). 4. Both methods give the same difference, \(1\frac{1}{3}\).

Answer

a) \(1\frac{1}{3}\) b) \(1\frac{1}{3}\)
5407494
Compare the two expressions. a) Evaluate \(\left(\frac{9}{12}-\frac{4}{12}\right)+\frac{2}{12}\). b) Evaluate \(\frac{9}{12}-\left(\frac{4}{12}+\frac{2}{12}\right)\). c) Explain why changing the grouping changes the result, and state the difference between the results.

Hints

- For parts a) and b), follow the parentheses before performing the remaining operation. - For part c), track whether the final term is added or included in the subtracted group. - Compare the two results in twelfths.

Solution

1. The first expression is \(\frac{5}{12}+\frac{2}{12}=\frac{7}{12}\). 2. The second expression is \(\frac{9}{12}-\frac{6}{12}=\frac{3}{12}=\frac{1}{4}\). 3. In the first expression, \(\frac{2}{12}\) is added after the subtraction. In the second, it is included in the amount being subtracted. 4. Therefore, the first result is greater by \(\frac{7}{12}-\frac{3}{12}=\frac{4}{12}=\frac{1}{3}\).

Answer

a) \(\frac{7}{12}\) b) \(\frac{1}{4}\) c) The first expression adds \(\frac{2}{12}\), while the second subtracts it as part of the grouped amount. The first result is greater by \(\frac{1}{3}\).
5407514
Compare \(\frac{7}{10}+\frac{2}{10}\) with \(\frac{7}{10}-\frac{2}{10}\). Without first evaluating both expressions, determine how much greater the addition result is than the subtraction result. Then verify.

Hints

- Both expressions begin at the same fraction. - Compare moving up by an amount with moving down by that same amount. - Use direct calculation only as a final check.

Solution

1. The first expression adds \(\frac{2}{10}\), while the second subtracts \(\frac{2}{10}\) from the same starting value. 2. The results therefore differ by two copies of \(\frac{2}{10}\), which is \(\frac{4}{10}=\frac{2}{5}\). 3. Verification: \(\frac{7}{10}+\frac{2}{10}=\frac{9}{10}\) and \(\frac{7}{10}-\frac{2}{10}=\frac{5}{10}\). Their difference is \(\frac{4}{10}=\frac{2}{5}\).

Answer

The addition result is greater by \(\frac{2}{5}\). Indeed, \(\frac{9}{10}-\frac{5}{10}=\frac{4}{10}=\frac{2}{5}\).
5407524
Use the numerator cards \(1\), \(3\), and \(5\) exactly once in \(\frac{\square}{8}+\frac{\square}{8}-\frac{\square}{8}\). Make the greatest possible result. Find every arrangement that reaches the maximum and state the result.

Hints

- Decide which numerator should be subtracted to make the result as large as possible. - The remaining two numerators must fill the addition positions. - Check whether reversing the two addends creates a distinct arrangement with the same value.

Solution

1. To make the result greatest, subtract the smallest numerator, \(1\). 2. The other two numerators, \(3\) and \(5\), go in the addition positions. 3. Both addend orders give the same value: \(\frac{3}{8}+\frac{5}{8}-\frac{1}{8}=\frac{7}{8}\) and \(\frac{5}{8}+\frac{3}{8}-\frac{1}{8}=\frac{7}{8}\). 4. If \(3\) or \(5\) were subtracted instead, the result would be smaller.

Answer

\(\frac{3}{8}+\frac{5}{8}-\frac{1}{8}=\frac{7}{8}\) and \(\frac{5}{8}+\frac{3}{8}-\frac{1}{8}=\frac{7}{8}\)
5407534
The two number lines represent \(1\frac{7}{8}-\frac{5}{8}\) and \(2-\frac{6}{8}\). Explain how adding \(\frac{1}{8}\) to both the starting amount and the amount subtracted transforms the first expression into the second without changing the difference. Then find the common value.
Figure for problem 540753

Hints

- Compare how both endpoints change from the first subtraction to the second. - A difference is the distance between two values on a number line. - Use the subtraction with the whole-number minuend for the final calculation.

Solution

1. Add \(\frac{1}{8}\) to both numbers in the first subtraction: \(1\frac{7}{8}+\frac{1}{8}=2\) and \(\frac{5}{8}+\frac{1}{8}=\frac{6}{8}\). 2. Increasing both the minuend and subtrahend by the same amount preserves the distance between them. 3. Therefore, the expressions are equal. Compute \(2-\frac{6}{8}=1\frac{2}{8}=1\frac{1}{4}\).

Answer

The expressions are equal because adding \(\frac{1}{8}\) to both numbers preserves their difference. Each expression equals \(1\frac{1}{4}\).
5407544
Find every subtraction of two positive fractions with denominator \(8\) that equals \(\frac{3}{8}\). The first numerator may be at most \(8\). List all the subtraction equations.

Hints

- Translate the fraction equation into a numerator difference. - Increase both numerators together to preserve that difference. - Start with the smallest positive second numerator. - Stop when the first numerator reaches the stated maximum.

Solution

1. With equal denominators, the first numerator must be \(3\) greater than the second numerator. 2. Starting with the smallest positive second numerator gives numerator pairs \((4,1)\), \((5,2)\), \((6,3)\), \((7,4)\), and \((8,5)\). 3. Each pair gives a valid equation. 4. The next pair would begin with numerator \(9\), which exceeds the stated maximum, so the list is complete.

Answer

\(\frac{4}{8}-\frac{1}{8}=\frac{3}{8}\); \(\frac{5}{8}-\frac{2}{8}=\frac{3}{8}\); \(\frac{6}{8}-\frac{3}{8}=\frac{3}{8}\); \(\frac{7}{8}-\frac{4}{8}=\frac{3}{8}\); \(\frac{8}{8}-\frac{5}{8}=\frac{3}{8}\)
5407554
A marker starts at the blue point on the number line. It may make exactly one of these moves: add \(\frac{1}{10}\), add \(\frac{3}{10}\), subtract \(\frac{2}{10}\), or subtract \(\frac{4}{10}\). Match each move to its endpoint in tenths and identify whether any two moves reach the same endpoint.
Figure for problem 540755

Hints

- Read the starting fraction from the blue point and the tenths scale. - Apply each move independently to the same starting point. - Compare the four resulting endpoints only after all moves have been evaluated.

Solution

1. The blue point is at \(\frac{5}{10}\). 2. Adding \(\frac{1}{10}\) gives \(\frac{6}{10}\), and adding \(\frac{3}{10}\) gives \(\frac{8}{10}\). 3. Subtracting \(\frac{2}{10}\) gives \(\frac{3}{10}\), and subtracting \(\frac{4}{10}\) gives \(\frac{1}{10}\). 4. The four endpoints are distinct, so no two moves reach the same endpoint.

Answer

\(+\frac{1}{10}\rightarrow\frac{6}{10}\); \(+\frac{3}{10}\rightarrow\frac{8}{10}\); \(-\frac{2}{10}\rightarrow\frac{3}{10}\); \(-\frac{4}{10}\rightarrow\frac{1}{10}\). No two moves reach the same endpoint.
5407564
A quantity starts at \(2\frac{3}{8}\). Its changes are recorded in order. <table><tr><th>Step</th><th>Change</th></tr><tr><td>1</td><td>Add \(\frac{4}{8}\)</td></tr><tr><td>2</td><td>Subtract \(\frac{7}{8}\)</td></tr><tr><td>3</td><td>Add \(\frac{2}{8}\)</td></tr></table> a) Find the value after each step. b) Is the final value greater than or less than the starting value, and by how much?

Hints

- For part a), apply the changes in the listed order and keep a running value. - Keep the final fractional part in eighths for an easy comparison. - For part b), subtract the smaller of the start and final values from the larger, then state which value is greater.

Solution

1. After step 1: \(2\frac{3}{8}+\frac{4}{8}=2\frac{7}{8}\). 2. After step 2: \(2\frac{7}{8}-\frac{7}{8}=2\). 3. After step 3: \(2+\frac{2}{8}=2\frac{2}{8}\). 4. Compare the final value with the start: \(2\frac{3}{8}-2\frac{2}{8}=\frac{1}{8}\). The final value is \(\frac{1}{8}\) less than the starting value.

Answer

a) Step 1: \(2\frac{7}{8}\); step 2: \(2\); step 3: \(2\frac{2}{8}\) b) The final value is \(\frac{1}{8}\) less than the starting value.
5407574
A fraction machine subtracts \(\frac{3}{8}\) from its input and then adds \(\frac{1}{8}\). The output is \(\frac{5}{8}\). Find the input by reversing the two machine steps, and verify it with the forward operations.

Hints

- Undo the machine operations in reverse order. - Use the inverse operation for each step. - Run the found input through the original machine to check it.

Solution

1. Reverse the final addition by subtracting \(\frac{1}{8}\): \(\frac{5}{8}-\frac{1}{8}=\frac{4}{8}\). 2. Reverse the first subtraction by adding \(\frac{3}{8}\): \(\frac{4}{8}+\frac{3}{8}=\frac{7}{8}\). 3. Verification: \(\frac{7}{8}-\frac{3}{8}+\frac{1}{8}=\frac{4}{8}+\frac{1}{8}=\frac{5}{8}\).

Answer

The input is \(\frac{7}{8}\). Checking forward, \(\frac{7}{8}-\frac{3}{8}+\frac{1}{8}=\frac{5}{8}\).
5407594
Evaluate \(1\frac{2}{8}-\frac{3}{8}-\frac{4}{8}\) and \(1\frac{2}{8}-\frac{4}{8}-\frac{3}{8}\). Do the two subtraction orders give the same result? Explain why.

Hints

- Carry out each order separately from the same starting amount. - Add the two removed fractions to compare the total removed. - Distinguish changing the order of removals from reversing the entire subtraction.

Solution

1. First order: \(1\frac{2}{8}-\frac{3}{8}=\frac{7}{8}\), then \(\frac{7}{8}-\frac{4}{8}=\frac{3}{8}\). 2. Second order: \(1\frac{2}{8}-\frac{4}{8}=\frac{6}{8}\), then \(\frac{6}{8}-\frac{3}{8}=\frac{3}{8}\). 3. Both orders remove a total of \(\frac{7}{8}\) from the same starting value, so they have the same result.

Answer

Both orders give \(\frac{3}{8}\) because each removes a total of \(\frac{7}{8}\) from the same starting value.
5407604
Use proper fractions with denominator \(8\) to give three addition examples: a) a sum less than \(1\); b) a sum equal to \(1\); c) a sum greater than \(1\). Explain how the numerator sum determines which kind of result occurs.

Hints

- Keep the denominator \(8\) and focus on the two numerators. - For the three parts, make the numerator sum less than \(8\), equal to \(8\), and greater than \(8\). - Check that each addend is still a proper fraction.

Solution

1. A sum less than \(1\) is \(\frac{2}{8}+\frac{3}{8}=\frac{5}{8}\), because \(2+3<8\). 2. A sum equal to \(1\) is \(\frac{3}{8}+\frac{5}{8}=\frac{8}{8}=1\), because \(3+5=8\). 3. A sum greater than \(1\) is \(\frac{5}{8}+\frac{6}{8}=\frac{11}{8}\), because \(5+6>8\). 4. With a common denominator of \(8\), compare the numerator sum with \(8\): less than, equal to, or greater than \(8\) determines the result’s relation to \(1\).

Answer

a) \(\frac{2}{8}+\frac{3}{8}=\frac{5}{8}\) b) \(\frac{3}{8}+\frac{5}{8}=1\) c) \(\frac{5}{8}+\frac{6}{8}=\frac{11}{8}\) Compare the numerator sum with \(8\) to determine whether the result is less than, equal to, or greater than \(1\).
5407614
Before calculating exactly, decide whether \(4\frac{1}{6}-2\frac{5}{6}\) is between \(0\) and \(1\), between \(1\) and \(2\), or greater than \(2\). Justify the estimate with nearby benchmarks, then find the exact difference.

Hints

- Bound each mixed number with nearby halves or whole numbers. - Use the bounds to place the difference in a one-unit interval. - Regroup only after making the estimate.

Solution

1. Since \(4\frac{1}{6}>4\) and \(2\frac{5}{6}<3\), the difference is greater than \(1\). 2. Since \(4\frac{1}{6}<4\frac{1}{2}\) and \(2\frac{5}{6}>2\frac{1}{2}\), the difference is less than \(2\). 3. Regroup: \(4\frac{1}{6}=3\frac{7}{6}\). 4. Then \(3\frac{7}{6}-2\frac{5}{6}=1\frac{2}{6}=1\frac{1}{3}\), which matches the estimate.

Answer

The difference is between \(1\) and \(2\): the whole-number bounds show it is greater than \(1\), and the half-unit bounds show it is less than \(2\). The exact difference is \(1\frac{1}{3}\).
5407624
The whole number \(n\) can be any value from \(0\) through \(8\). Classify every value of \(n\) according to whether \(\frac{5}{8}+\frac{n}{8}\) is a proper fraction, exactly \(1\), or greater than \(1\).

Hints

- Combine the numerator counts while keeping eighths as the unit. - Compare the resulting numerator with \(8\). - Include every allowed value of \(n\) in exactly one category.

Solution

1. The sum is \(\frac{5+n}{8}\). 2. It is proper when \(5+n<8\), which occurs for \(n=0, 1, 2\). 3. It equals \(1\) when \(5+n=8\), so \(n=3\). 4. It is greater than \(1\) when \(5+n>8\), which occurs for \(n=4, 5, 6, 7, 8\).

Answer

Proper: \(n=0, 1, 2\) Exactly \(1\): \(n=3\) Greater than \(1\): \(n=4, 5, 6, 7, 8\)
5407644
The bar shows an amount to subtract from \(1\), split into a blue part and an orange part. Subtract the blue part first and then the orange part. Show the two subtraction steps, state the final result, and explain why the two-step method removes exactly the shaded amount.
Figure for problem 540764

Hints

- Read each colored part as a fraction of the twelve equal sections. - Subtract the larger, familiar benchmark amount first. - Check that the two colored parts together equal the entire shaded amount being removed.

Solution

1. The blue part is \(\frac{6}{12}=\frac{1}{2}\), and the orange part is \(\frac{1}{12}\). Together they make \(\frac{7}{12}\). 2. Subtract the blue part first: \(1-\frac{1}{2}=\frac{1}{2}=\frac{6}{12}\). 3. Then subtract the orange part: \(\frac{6}{12}-\frac{1}{12}=\frac{5}{12}\). 4. The two removed parts total \(\frac{7}{12}\), so this is the same as \(1-\frac{7}{12}\).

Answer

\(1-\frac{1}{2}=\frac{6}{12}\), then \(\frac{6}{12}-\frac{1}{12}=\frac{5}{12}\). The final result is \(\frac{5}{12}\).
5407654
A roll of ribbon is \(3\frac{2}{5}\) yards long. Mia uses \(1\frac{4}{5}\) yards for a project. Write a subtraction equation and find how much ribbon remains.

Hints

- Subtract the amount used from the starting ribbon length. - Compare the two fractional parts before subtracting. - If needed, regroup one whole as fifth-sized parts.

Solution

1. Subtract the used length from the starting length: \(3\frac{2}{5}-1\frac{4}{5}\). 2. Regroup \(3\frac{2}{5}\) as \(2\frac{7}{5}\). 3. Then \(2\frac{7}{5}-1\frac{4}{5}=1\frac{3}{5}\). 4. Therefore, \(1\frac{3}{5}\) yards of ribbon remains.

Answer

\(3\frac{2}{5}-1\frac{4}{5}=1\frac{3}{5}\); \(1\frac{3}{5}\) yards remains.
5407664
Write a one-sentence situation that is modeled by \(\frac{10}{12}-\frac{4}{12}+\frac{1}{12}\). The situation must make the subtraction happen before the addition. Then find the final amount.

Hints

- Begin with an amount that can decrease and then increase. - Describe the removal before the later addition. - Check that the situation’s final amount matches the expression.

Solution

1. One valid situation is: “A water bottle is \(\frac{10}{12}\) full, Sam drinks \(\frac{4}{12}\) of the bottle, and then adds \(\frac{1}{12}\) of the bottle.” 2. After drinking, the bottle is \(\frac{10}{12}-\frac{4}{12}=\frac{6}{12}\) full. 3. After adding water, it is \(\frac{6}{12}+\frac{1}{12}=\frac{7}{12}\) full. 4. Other situations are valid if they represent the same ordered changes.

Answer

One possible situation: A water bottle is \(\frac{10}{12}\) full, Sam drinks \(\frac{4}{12}\) of the bottle, and then adds \(\frac{1}{12}\) of the bottle. The final amount is \(\frac{7}{12}\).
5407674
The model shows how full a water bottle is at first. Leo drinks \(\frac{2}{10}\) of the bottle and then adds \(\frac{1}{10}\) of the bottle. Leo says the bottle is now \(\frac{4}{10}\) full. Is Leo correct? Explain and find the correct final amount.
Figure for problem 540767

Hints

- Read the starting amount from the tenths model. - Apply the two changes in the order stated. - Compare Leo's value with the amount after both changes have been made.

Solution

1. The model shows an initial amount of \(\frac{6}{10}\). 2. After Leo drinks, \(\frac{6}{10}-\frac{2}{10}=\frac{4}{10}\) remains. 3. He then adds \(\frac{1}{10}\), giving \(\frac{4}{10}+\frac{1}{10}=\frac{5}{10}\). 4. Leo stopped after the subtraction and ignored the final addition, so his claim is incorrect.

Answer

Leo is not correct. The final amount is \(\frac{5}{10}\) of the bottle.
5408384
Nora writes \(\frac{9}{12}-\frac{3}{12}=\frac{6}{0}\) because she subtracts both numerators and denominators. Explain why the denominator must remain \(12\), and correct the result using unit-fraction language.

Hints

- Name the size of one part before subtracting. - Subtraction changes how many equal parts remain, not how each part is partitioned. - Simplify only after writing the correct like-denominator difference.

Solution

1. Both fractions count parts of size \(\frac{1}{12}\), so subtraction removes three twelfth-sized parts from nine twelfth-sized parts. 2. The size of each remaining part does not change; only the number of parts changes. 3. Six twelfth-sized parts remain: \(\frac{9}{12}-\frac{3}{12}=\frac{6}{12}=\frac{1}{2}\).

Answer

The denominator remains \(12\) because the parts are still twelfth-sized. Six twelfths remain, so \(\frac{9}{12}-\frac{3}{12}=\frac{6}{12}=\frac{1}{2}\).
5407414
Two ribbon pieces are each measured in twelfths of a yard. Together they are \(\frac{5}{6}\) yard long. The longer piece is \(\frac{1}{6}\) yard longer than the shorter piece. Find the length of each ribbon piece.

Hints

- Convert both the total length and the difference to twelfths. - Search for two numerators with the required total and gap. - Verify both conditions with the two ribbon lengths.

Solution

1. Rewrite the conditions in twelfths: the numerator sum is \(10\), and the numerator difference is \(2\). 2. The two whole-number numerators that add to \(10\) and differ by \(2\) are \(4\) and \(6\). 3. The ribbon lengths are \(\frac{4}{12}=\frac{1}{3}\) yard and \(\frac{6}{12}=\frac{1}{2}\) yard. 4. Their sum is \(\frac{10}{12}=\frac{5}{6}\) yard, and their difference is \(\frac{2}{12}=\frac{1}{6}\) yard.

Answer

\(\frac{4}{12}\) yard and \(\frac{6}{12}\) yard, or \(\frac{1}{3}\) yard and \(\frac{1}{2}\) yard
5407584
The same whole number belongs in both boxes: \(\frac{\square}{10}+\frac{3}{10}=\frac{9}{10}-\frac{\square}{10}\). Find the whole number and verify that both sides have the same value.

Hints

- The same numerator must be used in both boxes. - Think about what happens to the left side and right side as that numerator increases. - Test a value near the middle and compare the two sides.

Solution

1. Try the same numerator in both boxes while keeping all parts in tenths. 2. With \(3\) in each box, the left side is \(\frac{3}{10}+\frac{3}{10}=\frac{6}{10}\). 3. The right side is \(\frac{9}{10}-\frac{3}{10}=\frac{6}{10}\). 4. A smaller box value would make the left side smaller and the right side larger; a larger box value would do the opposite. Therefore, \(3\) is the only value that balances the equation.

Answer

\(3\); both sides equal \(\frac{6}{10}\).
5407634
Cards A–D show four different fractions in eighths. Divide the four cards into two pairs with equal sums. Use every card exactly once. Find the pairing and explain why no other pairing works.
Figure for problem 540763

Hints

- Read each card's value from the eighths model. - Find the total value of all four cards and determine what half of that total must be. - Test the possible partners for the smallest card.

Solution

1. The cards show A \(=\frac{1}{8}\), B \(=\frac{2}{8}\), C \(=\frac{3}{8}\), and D \(=\frac{4}{8}\). 2. All four cards total \(\frac{10}{8}\), so each equal pair must total \(\frac{5}{8}\). 3. A and D make \(\frac{1}{8}+\frac{4}{8}=\frac{5}{8}\). The remaining cards B and C also make \(\frac{2}{8}+\frac{3}{8}=\frac{5}{8}\). 4. If A were paired with B or C, that pair would total less than \(\frac{5}{8}\). Therefore, A must pair with D, which forces the other pair.

Answer

Pair A with D and pair B with C. Each pair totals \(\frac{5}{8}\).

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