New
New
Year 2

Add three addends efficiently by finding two addends that total 10

I can use my knowledge of number pairs to 10 to add three addends efficiently.

New
New
Year 2

Add three addends efficiently by finding two addends that total 10

I can use my knowledge of number pairs to 10 to add three addends efficiently.

Lesson details

Key learning points

  1. The order of the addends can change and the sum stays the same.
  2. When adding three addends, it is efficient to first find two addends that sum to 10
  3. ___ add ___ is equal to 10 Then, 10 add ___ is equal to ___

Common misconception

If children record incorrectly, they could re-add an addend that has already been used to make a pair to 10

Carefully model how to record thinking, rewriting the new equation inclusive of 10 underneath.

Keywords

  • Addends - Any of the numbers that are added together.

  • Number pairs - Two numbers that sum to make 10

  • Efficient - Not wasting time or effort. An efficient strategy is one we can carry out easily.

When adding three addends, always encourage children to see if they can find two addends that sum to 10 before adding the third addend. Outside of the lesson, build speed in recalling the pairs to 10 through quizzing and games.
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).

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6 Questions

Q1.
Match the number pairs to 10
Correct Answer:1,9

9

Correct Answer:3,7

7

Correct Answer:5,5

5

Correct Answer:4,6

6

Correct Answer:2,8

8

Q2.
'Make 10' by adding the third addend.
Correct Answer:1 + 3,+ 6

+ 6

Correct Answer:2 + 4,+ 4

+ 4

Correct Answer:3 + 5,+ 2

+ 2

Correct Answer:4 + 1,+ 5

+ 5

Q3.
Match each double fact to the correct answer.
Correct Answer:Double 5,10

10

Correct Answer:6 + 6,12

12

Correct Answer:Double 9,18

18

Correct Answer:7 + 7,14

14

Correct Answer:Double 8 ,16

16

Q4.
Find the sum of the three addends and compare this to 10
Correct Answer:3 + 5 + 4,greater than 10

greater than 10

Correct Answer:5 + 2 + 1,less than 10

less than 10

Correct Answer:5 + 3 + 2,equal to 10

equal to 10

Q5.
Which step has been taken in solving this equation?
An image in a quiz
Using a known double fact.
Finding the total of the first two addends.
Correct answer: Using a known number pair to 10
Q6.
Solve this equation using an efficient strategy. 1 + 4 + 5 =
Correct Answer: 10

6 Questions

Q1.
Which number pairs are not pairs to 10?
9 and 1
Correct answer: 2 and 7
4 and 6
Correct answer: 8 and 3
3 and 7
Q2.
Which expressions include two addends that are a number pair to 10?
Correct answer: 8 + 5 + 2
4 + 3 + 2
Correct answer: 1 + 9 + 2
Correct answer: 3 + 4 + 7
Q3.
Which are correct?
4 + 4 + 1 > 10
5 + 3 + 2 < 10
Correct answer: 5 + 3 + 5 > 10
Correct answer: 2 + 7 + 1 = 10
Correct answer: 3 + 4 + 2 < 10
Q4.
Which two addends are a number pair to 10?
An image in a quiz
6 and 8
8 and 4
Correct answer: 6 and 4
Q5.
Look at this equation and complete the stem sentence. 5 + 5 is equal to 10, then 10 + 4 is equal to
An image in a quiz
Correct Answer: 14
Q6.
Look at the part-part-whole model. Say the stem sentence aloud to find the sum ___ add ___ is equal to 10, then 10 add ___ is equal to
An image in a quiz
Correct Answer: 16