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Florida Grade 3 Math · Algebraic Reasoning

MA.3.AR.2.3: Finding the Unknown in Multiplication and Division

What this Grade 3 benchmark means, worked examples, common mistakes, and a free printable worksheet.

Created by a Florida mom · Published by Tropical Learning LLC

Download Free Worksheet (PDF)See worked examples

What Is Benchmark MA.3.AR.2.3?

Students find the unknown whole number in a multiplication or division equation with three numbers. The unknown can be in any position and on either side of the equal sign, and it can be shown with a symbol or a letter.

Factors are up to 12. Related facts are the key: if 7 × 9 = 63, then 63 ÷ 7 = 9 and 63 ÷ 9 = 7.

Official benchmarkDetermine the unknown whole number in a multiplication or division equation, relating three whole numbers, with the unknown in any position.

On the FAST test: part of the Grade 3 reporting category Number Sense and Multiplicative Reasoning, which is about 23–29% of the test.

Worked Examples

Worked Example 1

Missing Factor

7 × □ = 63
  1. 1Think: 7 times what is 63?
  2. 27 × 9 = 63
Answer: □ = 9

Worked Example 2

Missing Total in Division

n ÷ 4 = 8
  1. 1Some number split into 4 equal groups gives 8 in each group.
  2. 2The total is 4 × 8 = 32
  3. 3Check: 32 ÷ 4 = 8
Answer: n = 32

Common Mistakes to Watch For

Adding instead of using related facts

Wrong:□ ÷ 6 = 5, so □ = 11

What number divided by 6 is 5? 6 × 5 = 30, so □ = 30.

Getting stuck when the unknown is on the right

Wrong:48 = 6 × □ can't be solved because the answer is on the left.

Read it as 6 × □ = 48. Since 6 × 8 = 48, □ = 8.

Helpful Math Tip

Put the answer back into the equation and check that it makes a true statement.

Related Grade 3 Skills

MA.3.AR.2.1

Division as a Missing Factor

MA.3.AR.2.2

True or False Multiplication and Division Equations

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Independent Educational Platform. FastChomp is published by Tropical Learning LLC and is not affiliated with, sponsored by, or endorsed by the Florida Department of Education. FAST and Star assessment names are referenced for informational purposes only. FastChomp practice questions are original educational materials, not official Florida FAST assessment questions.