New
New
Year 3

Numbers can be added in any order

I understand that numbers can be added in any order.

New
New
Year 3

Numbers can be added in any order

I understand that numbers can be added in any order.

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Lesson details

Key learning points

1. The order we add the addends does not change the sum.
3. Commutative means that we can change the order of the addends and the sum stays the same.

Common misconception

Pupils perceive the equals sign = as 'where the answer goes' and struggle with writing equations.

Show pupils that the equals sign represents balance and that equations are equal on both sides of the sign. Balance scales can be used.

Keywords

• Commutative - Addition is commutative. This means the order of the addends can be changed without changing the calculation or sum.

• Equation - An equation is used to show that one number or calculation is equal to another.

• Sum - The sum is the total after numbers are added together.

Commutativity means we should be looking for the most efficient way of finding a sum to an addition calculation. Encourage children to use doubles and number pairs that total 10 to find an answer.
Teacher tip

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

Starter quiz

6 Questions

Q1.
Which equation is represented by the tens frame?
4 + 3 + 1 = 8
4 + 2 + 2 = 8
5 + 3 = 8
Correct answer: 5 + 2 + 1 = 8
Q2.
What is the sum of the numbers in the bar model?
8
9
11
Q3.
What addend is missing from the bar model?
Q4.
Which three dice have a sum of 11?
Correct Answer: An image in a quiz
Q5.
What is the sum of 5 and 5 and 8?
Q6.
Alex chooses 3 of the number cards and adds them together. Which 3 cards did he choose if he gets a sum of 14?
4 and 5 and 6
Correct answer: 3 and 5 and 6
3 and 4 and 6
3 and 4 and 5

Exit quiz

6 Questions

Q1.
Which two calculations have the same sum as 4 + 3 + 1?
Correct answer: 1 + 3 + 4
4 + 2 + 3
1 + 2 + 4
Correct answer: 4 + 1 + 3
Q2.
Alex has these 3 number cards. What is the most sensible order to add them to find the sum?
3 + 1 + 8
1 + 3 + 8
Correct answer: 8 + 3 + 1
Q3.
What is the missing addend in this equation?