1.OA.3: Use Properties to Add and Subtract
Also written as 1.OA.B.3 and CCSS.MATH.CONTENT.1.OA.B.3 · Cluster: Understand and apply properties of operations and the relationship between addition and subtraction.
The Official Wording
Apply properties of operations as strategies to add and subtract. Examples: If 8 + 3 = 11 is known, then 3 + 8 = 11 is also known. (Commutative property of addition.) To add 2 + 6 + 4, the second two numbers can be added to make a ten, so 2 + 6 + 4 = 2 + 10 = 12. (Associative property of addition.)
Common Core State Standards, Grade 1, Operations & Algebraic Thinking · Read it at the source · Checked October 14, 2026
What 1.OA.3 Means in Plain English
First graders use two rules about adding without needing their names. Order does not matter, so a child who knows 9 + 2 = 11 already knows 2 + 9. Grouping does not matter either, so 5 + 5 can go first in 3 + 5 + 5.
The payoff is fewer facts to learn and easier sums: start from the bigger number, or find the ten. Subtraction does not turn around, which some children test early. In 2nd grade students explain why their strategies work, using place value and these properties (2.NBT.9).
1.OA.3 I Can Statements
- I can turn an addition fact around and know the sum.
- I can choose which two numbers to add first.
- I can make a ten to add three numbers.
1.OA.3 Worked Example
One three-number sum rearranged twice, once with each property, so the ten does the work.
Add 3 + 8 + 7 the easy way.
- Read all three numbers and look for a pair that makes ten. 3 and 7 do.3 + 8 + 7
- Turn the 8 and the 7 around so the partners sit together. Order does not change the total.3 + 7 + 8
- Group the partners and add them first.3 + 7 = 10, so 10 + 8
- A ten and 8 more is eighteen.10 + 8 = 18
Check it: Add in the printed order: 3 + 8 = 11, and 11 + 7 = 18. The total did not change, which is the whole point.
Common Mistakes with 1.OA.3
Counting on from the smaller number
For 2 + 9, starts at 2 and counts nine fingers to reach 11
Try this: Ask which number is bigger, start there, and count on only the small one: 9, then 10, 11.
Turning subtraction around
9 - 4 = 5, so 4 - 9 = 5 too
Try this: Model it with cubes: take 4 from 9 easily, then try taking 9 from a tower of 4 and talk about why it fails.
Not trusting the turn-around
Knows 7 + 2 = 9 but solves 2 + 7 by counting from 1
Try this: Build 7 + 2 as a cube train, flip the train end to end, and ask whether any cubes were added or lost.
Where 1.OA.3 Fits
Practice 1.OA.3
Quick Check
- Zoe knows 9 + 5 = 14. What is 5 + 9?
- Which two numbers would you add first in 6 + 7 + 4? What is the total?
- Is 3 + 8 the same as 8 + 3? Which one is faster to count on?