CCSS.Math.Content.1.OA.B

CCSS.Math.Content.1.OA.B is a cluster heading. These are the individual standards under it.

• CCSS.Math.Content.1.OA.B.3

  Apply properties of operations as strategies to add and subtract.

• CCSS.Math.Content.1.OA.B.4

  Understand subtraction as an unknown-addend problem.

01

What Students Need to Do

Students change the order or grouping of numbers to make addition easier. They use addition facts to solve subtraction problems by finding a missing part.

02

What Mastery Looks Like

Students rearrange or group numbers to make an addition problem easier. They solve a subtraction problem by finding the missing part and check it with addition.

03

Common Misconceptions

Students may think changing the order of numbers changes an addition answer. They may reverse numbers in subtraction or miss that an addition fact can solve a related subtraction fact.

04

How to Assess It

Give this exit ticket: Solve 4 + 7 + 6 and 13 − 5. Show a helpful rearrangement for the first, then write an addition equation that proves the second.

1. 01

   Use two-color counters to build 3 + 5 and 5 + 3, then compare totals and record both equations.

2. 02

   Ask, “How can 6 + 4 help you solve 10 − 6?” Students draw and explain the missing part.

3. 03

   Play equation match with cards such as 7 + 2, 2 + 7, 9 − 7, and 9 − 2, matching related facts.

4. 04

   Set up a snack problem: 12 crackers, 5 eaten; students use 5 + ? = 12 to find how many remain.

• CCSS.Math.Content.1.NBT.C

  Use place value understanding and properties of operations to add and subtract.

• CCSS.Math.Content.2.OA.A

  Represent and solve problems involving addition and subtraction.

• CCSS.Math.Content.2.NBT.B

  Use place value understanding and properties of operations to add and subtract.