Apply the Associative Property of Addition

Students will understand that when adding three numbers, they can group any two of them first and the sum stays the same. Students use this strategy to find friendly pairs (like numbers that make 10) when adding three addends.

Try three of them

Real questions from this skill, graded here. No account, and nothing is saved.

Grade 1 · Properties and Strategies for Addition and Subtraction · question 1 of 3

0 of 12

12 rungs. A star at the top.

6 + (4 + 3) =

How it is taught

0:00 of 2:35

You can add any pair first.

A pair that makes ten is easy.

Read it: Group any 2 numbers first

4 + 3 + 6: add 4 and 6 first to make 10, then add 3. (4 + 6) + 3 = 13.

Look for 2 numbers that make 10: 4 and 6.
Group them first: (4 + 6) + 3.
Add: 10 + 3 = 13.

You can group the numbers in any way, and the total stays the same.

(4 + 3) + 6 is 13, and 4 + (3 + 6) is 13 too.

Grouping 2 that make 10 first makes the adding easier.

Group any 2 first. The total does not change.

Thinking the numbers must be added in the order they are written.

Any 2 can go first. (4 + 6) + 3 = 13.

Ana has 7 shells, 4 shells and 3 shells. How many shells? — 14. 7 + 3 = 10, and 4 more is 14.

8 + 2 + 6

Let's add three numbers: eight plus two plus six. We can group any two of them first!

Here are our three numbers, all lined up to add.

Let's look for a friendly pair — two numbers that make ten.

Eight and two make ten! That's our friendly pair.

Let's group them with parentheses, so we add them first.

Eight plus two is ten.

Now ten plus six is sixteen.

We can group any two numbers first and the sum stays the same. That's the associative property.

Grade 1 · Group friendly pairs that make 10

Eight plus two plus six is sixteen. Finding tens makes adding so much easier!

What you see

While they climb, your page writes one true line to ask about tonight, and a short note each Sunday.

MayaGrade 3 · Mathematics

Did you know?

A chessboard has 64 squares — share them out between the 8 rows and each row holds exactly 8.

Today’s goal: 1 star — one skill mastered, every rung of its ladder climbed
Climbing now: Divide within 100

An example student.

MayaGrade 3 · Mathematics

Maya earned 2 stars this week — Interpret multiplication as equal groups, which took 6 answers over 3 days before its star landed 3 days ago and Multiply by 6, 7, 8 and 9. Next up: Divide within 100.

An example week.

More of the library

Every skill has a page

Practise this skill free

14 days of every skill, practice packets, Fluency sheets and up to four students. No card.

Start free