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Florida Grade 1 Math · Algebraic Reasoning

MA.1.AR.2.1: Subtraction as a Missing Addend

What this Grade 1 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.1.AR.2.1?

Children learn that every subtraction problem can be turned into an addition problem with a missing number. For example, 12 − 7 = ? can be written as 7 + ? = 12, and since 7 + 5 = 12, the answer is 5.

Sums are up to 20. This connection makes subtraction facts much easier to remember.

Official benchmarkRestate a subtraction problem as a missing addend problem using the relationship between addition and subtraction.

How it is tested: Grade 1 students take FAST Star Math, Florida's math test for Kindergarten through Grade 2.

Worked Examples

Worked Example 1

Rewrite and Solve

Rewrite 15 − 9 = ? as an addition problem, then solve it.
  1. 1Ask: 9 plus what makes 15?
  2. 2Write it as 9 + ? = 15.
  3. 39 + 6 = 15, so ? = 6.
Answer: 9 + ? = 15; the answer is 6

Worked Example 2

Another One

Use addition to solve 13 − 8.
  1. 1Think: 8 + ? = 13
  2. 28 + 5 = 13
Answer: 5

Common Mistakes to Watch For

Adding the two numbers

Wrong:12 − 7 = ? becomes 12 + 7 = ?

Keep the total (12) by itself: 7 + ? = 12.

Using the total as the missing number

Wrong:7 + ? = 12, so ? = 19

The missing number plus 7 must make 12: 7 + 5 = 12, so ? = 5.

Helpful Math Tip

When your child is stuck on a subtraction fact, ask, "What do you add to the smaller number to get the bigger one?"

Related Grade 1 Skills

MA.1.NSO.2.1

Addition Facts to 10

MA.1.AR.2.3

Finding the Missing Number

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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.