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Unknown factor problems

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5503693
Find the missing factor: \(\square \times 6 = 42\).

Hints

- Ask what number multiplied by \(6\) gives \(42\). - Use a familiar \(6\)s multiplication fact. - Check by multiplying your factor by \(6\).

Solution

1. Think of the multiplication fact that makes \(42\) with a factor of \(6\). 2. Since \(7 \times 6 = 42\), the missing factor is \(7\).

Answer

\(7\)
5157743
Find each missing factor. a) \(\square \times 7=42\) b) \(9 \times \square=72\) c) \(\square \times 6=24\) d) \(\square \times 3=27\)

Hints

- In every part, the blank is one factor rather than the product. - Use a related division fact when the product and one factor are known. - Check each result by multiplying the two factors.

Solution

1. Since \(6 \times 7=42\), the missing factor in part a is \(6\). 2. Since \(9 \times 8=72\), the missing factor in part b is \(8\). 3. Since \(4 \times 6=24\), the missing factor in part c is \(4\). 4. Since \(9 \times 3=27\), the missing factor in part d is \(9\).

Answer

a) \(6\) b) \(8\) c) \(4\) d) \(9\)
5169693
An animal shelter needs \(\$24\) for enrichment supplies. Each sponsor gives \(\$4\). How many sponsors are needed to raise exactly \(\$24\)?

Hints

- Think of the total as equal groups of \(\$4\). - Use a multiplication fact with an unknown factor. - Check that the contributions add to \(\$24\).

Solution

1. Let \(n\) be the number of sponsors. The equal contributions give \(4 \times n = 24\). 2. Since \(4 \times 6 = 24\), \(n = 6\).

Answer

\(6\) sponsors are needed.
5182223
Ben says, “When I multiply my number by \(3\), I get \(30\).” Mia says, “My number is \(4\) greater than Ben's number.” What number is Mia thinking of?

Hints

- Find Ben's number first. - Use division to undo multiplication by \(3\). - Then add \(4\).

Solution

1. Find Ben’s number: \(30 \div 3 = 10\). 2. Mia’s number is \(10 + 4 = 14\).

Answer

Mia is thinking of \(14\).
5200024
The product of two numbers is \(320\). One factor is \(8\). What is the other factor?

Hints

- Think of the missing factor as the number that makes \(8\times\square=320\). - Use division by the known factor to find the missing factor. - Check your quotient by multiplying it by \(8\).

Solution

1. Divide the product by the known factor: \(320\div8=40\). 2. Check: \(8\times40=320\).

Answer

The other factor is \(40\).
5201053
What number makes this division equation true? \(48\div\square=6\) Write the complete equation.

Hints

- Use a multiplication fact with \(6\) and \(48\). - What number times \(6\) equals \(48\)? - Put that number in the division equation and check it.

Solution

1. Ask what number multiplied by \(6\) gives \(48\). 2. \(6\times8=48\), so the missing number is \(8\). 3. The complete equation is \(48\div8=6\).

Answer

\(48\div8=6\)
5503503
A rectangular array has \(28\) tiles arranged in \(4\) equal rows. Complete the equation \(4 \times n=28\). What does \(n\) represent in the array?

Hints

- One factor is the number of rows, and the product is the total number of tiles. - The unknown factor describes the equal size of each row. - Use the related division fact to find \(n\).

Solution

1. The unknown factor tells how many tiles are in each row. 2. Since \(28 \div 4=7\), \(n=7\). 3. Thus, the array has \(7\) tiles in each row.

Answer

\(n=7\). It represents the number of tiles in each row.
5192373
Four times a number is the same as \(50-10\). a) Write an equation using \(n\) for the unknown number. b) Find \(n\).

Hints

- “Four times \(n\)” is \(4\times n\). - Find \(50-10\). - What number multiplied by \(4\) gives that result?

Solution

1. The equation is \(4 \times n=50-10\). 2. \(50-10=40\), so \(4 \times n=40\). 3. Since \(4 \times 10=40\), \(n=10\).

Answer

a) \(4 \times n=50-10\) b) \(n=10\)
5207853
Find the amount being subtracted each time. Use \(n\) for the unknown amount. a) Starting at \(36\), subtract the same amount \(4\) times to reach \(0\). What is \(n\)? b) Starting at \(63\), subtract the same amount \(7\) times to reach \(0\). What is \(n\)?

Hints

- Repeated subtraction to \(0\) can be represented by equal groups. - In each part, the number of subtractions is one factor and \(n\) is the other factor. - Use division to find the missing number from the starting total.

Solution

1. In part a, the repeated amount is the missing number in \(4 \times n=36\). Since \(36 \div 4=9\), \(n=9\). 2. In part b, the repeated amount is the missing number in \(7 \times n=63\). Since \(63 \div 7=9\), \(n=9\).

Answer

a) \(n=9\) b) \(n=9\)
5363013
Fill in the missing numbers in the product wall. Each brick is the product of the two bricks directly below it. Each time you find a missing lower brick, write the division equation you used.
Figure for problem 536301

Hints

- If you know a product and one number below it, divide to find the other number. - Start where a product and one number below it are both known. - Write the division equation before moving to the next missing brick.

Solution

1. The left bottom brick satisfies \(\square \times 4=8\), so \(8 \div 4=2\). 2. The missing right brick in the second row satisfies \(8 \times \square=64\), so \(64 \div 8=8\). 3. The right bottom brick satisfies \(4 \times \square=8\), so \(8 \div 4=2\). 4. The completed bottom row is \(2,4,2\), and the missing second-row value is \(8\).

Answer

Left bottom: \(8 \div 4=2\) Second-row right: \(64 \div 8=8\) Right bottom: \(8 \div 4=2\) Bottom row: \(2,4,2\) Second row: \(8,8\) Top: \(64\)
5363033
Complete the product wall. Each upper brick is the product of the two bricks directly below it.
Figure for problem 536303

Hints

- Use division to find a missing factor when the product and the other factor are known. - Check by multiplying from the bottom upward.

Solution

1. The bottom-left factor must satisfy \(\square \times 2=8\), so it is \(8 \div 2=4\). 2. The right factor in the second row must satisfy \(8 \times \square=48\), so it is \(48 \div 8=6\). 3. The bottom-right factor must satisfy \(2 \times \square=6\), so it is \(6 \div 2=3\).

Answer

Bottom row: \(4\), \(2\), \(3\) Second row: \(8\), \(6\) Top: \(48\)
5363183
Complete this product wall. Each upper brick is the product of the two bricks directly below it.
Figure for problem 536318

Hints

- Use division to find a missing factor when the product is known. - Start with a small triangle in which two of the three values are known. - Check that every multiplication from bottom to top is correct.

Solution

1. The left brick in the second row must satisfy \(\square \times 10=80\), so it is \(8\). 2. The middle bottom value must satisfy \(4 \times \square=8\), so it is \(2\). 3. The right bottom value must satisfy \(2 \times \square=10\), so it is \(5\).

Answer

Bottom row: \(4\), \(2\), \(5\) Second row: \(8\), \(10\) Top: \(80\)
5503703
Two arrays each have \(42\) tiles. Array A has \(6\) rows. Array B has \(7\) rows. a) How many tiles are in each row of Array A? b) How many tiles are in each row of Array B? c) Write a multiplication equation with \(n\) for each array. Compare the two values of \(n\).

Hints

- Use the same total, \(42\), in both equations. - For Array A, ask: \(6\) times what number equals \(42\)? - For Array B, ask: \(7\) times what number equals \(42\)? Then compare the two missing numbers.

Solution

1. The first array has \(6\) rows and \(42\) dots, so \(6\times n=42\). Since \(6\times7=42\), \(n=7\). 2. The second array has \(7\) rows and \(42\) dots, so \(7\times n=42\). Since \(7\times6=42\), \(n=6\).

Answer

a) \(7\) tiles in each row b) \(6\) tiles in each row c) Array A: \(6\times n=42\), so \(n=7\). Array B: \(7\times n=42\), so \(n=6\). The values of \(n\) are \(7\) and \(6\).
5503713
The missing factor is a whole number from \(7\) through \(10\). \(6\times\square\) must be less than \(45\). What is the greatest number that can go in the box? Find the product and explain why the next larger choice does not work.

Hints

- Start with the smallest allowed whole-number factor greater than \(6\). - Test the products in increasing factor order. - Once a product is greater than \(45\), think about what happens with still larger factors.

Solution

1. The allowed whole-number factors begin with \(7, 8, 9,\) and \(10\). 2. \(6 \times 7 = 42\), which is less than \(45\). 3. The next factor gives \(6 \times 8 = 48\), which is greater than \(45\). Any larger allowed factor gives an even larger product. 4. Therefore, the greatest possible missing factor is \(7\), and the product is \(42\).

Answer

The greatest possible missing factor is \(7\), and the product is \(42\). The next choice, \(8\), gives \(6\times8=48\), which is not less than \(45\).

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