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Grade 3 math worksheets

Build your own math worksheets from 35,000+ problems for grades 3 to 12, from fractions to AP Calculus. Every problem comes with step-by-step solutions.

Unknown factor problems

Learning goals

  • Represents a missing-factor situation with a multiplication or division equation.
  • Finds the unknown factor using related facts or division.
  • Explains the multiplication-division relationship used.
  • Checks the factor in the original equation.

Click problems to add them to your worksheet.

Unknown factor problems 1
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

\(7\)
Unknown factor problems 2
Find the missing number: \(3\times\square=12\). Choose from \(3,4,5\) and check by multiplication.

Hints

- Think about three equal groups. - Try the possible numbers in the empty place.

Solution

1. Three groups of four make twelve. 2. The missing factor is \(4\), and \(3\times4=12\) checks it.

Answer

\(4\); check: \(3\times4=12\).
Unknown factor problems 3
Fill in \(\square\times\square=15\) using the picture, with the number of rows first. Explain what both factors count.
Figure for problem 558466

Hints

- Read the rows from the picture first. - Then find the number of dots in one row.

Solution

1. The picture shows \(5\) rows of \(3\) dots. 2. Complete the equation as \(5\times3=15\). The first factor counts rows, and the second counts dots per row.

Answer

\(5\times3=15\). The \(5\) counts rows; the \(3\) counts dots in each row.
Unknown factor problems 4
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) \(9\)
Unknown factor problems 5
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.
Unknown factor problems 6
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

\(48\div8=6\)
Unknown factor problems 7
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.
Unknown factor problems 8
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 \(45\).
Unknown factor problems 9
Find both missing factors: \(3\times\square=24\) and \(\square\times4=24\). Are the missing numbers the same? Check each equation.

Hints

- Could you build each product using equal groups? - Check each missing number in its own equation before comparing them.

Solution

1. Three groups of eight make \(24\), so the first missing factor is \(8\). 2. Six groups of four make \(24\), so the second missing factor is \(6\). 3. Check: \(3\times8=24\) and \(6\times4=24\). The missing factors differ.

Answer

The missing factors are \(8\) and \(6\); they are not the same. Checks: \(3\times8=24\), \(6\times4=24\).
Unknown factor problems 10
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) \(n=10\)
Unknown factor problems 11
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: \(64\)
Unknown factor problems 12
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: \(48\)
Unknown factor problems 13
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: \(80\)
Unknown factor problems 14
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 \(6\).

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