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Year 2

Use number facts to solve addition and subtraction problems.

I can use number facts to solve addition and subtraction problems.

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New
New
Year 2

Use number facts to solve addition and subtraction problems.

I can use number facts to solve addition and subtraction problems.

Download all resources
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Share activities with pupils
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Lesson details

Key learning points

  1. Known facts can be used to help find new facts efficiently.
  2. Known facts can be used to solve addition and subtraction problems.
  3. Bar models can be drawn to help represent and understand problems.

Keywords

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

  • Whole - All of something. Complete.

  • Part - A piece or section of a whole.

Common misconception

Children may have difficulty knowing which operation is required to solve a problem, particularly in those involving finding the difference.

Encourage children to draw bar models or part-part-whole models to support their understanding of the structure of the problem and to articulate their thinking (as modelled in the lesson).

Exploration of the same context, but with a different part missing each time, can support understanding of the structure of the problem. Understanding can be deepened by giving one problem and asking children to use the same context and numbers to make a new problem.
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).

Lesson video

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Starter quiz

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6 Questions

Q1.
Which number would complete the equation that comes next in the pattern?
An image in a quiz
Correct Answer: 24, twenty-four, twenty four
Q2.
Use the first part-part-whole model to complete the pattern.
An image in a quiz
Correct answer: 43 then 53
33 then 43
43 then 63
48 then 58
Q3.
Use a known fact to find the missing number. 34 + = 39
Correct Answer: 5, five
Q4.
Match the correct single digit fact to the equation that it could help solve.
Correct Answer:5 - 2 = 3 ,35 - 2 = 33

35 - 2 = 33

Correct Answer:7 - 4 = 3 ,97 - 4 = 93

97 - 4 = 93

Correct Answer:3 - 2 = 1,33 - 2 = 31

33 - 2 = 31

Q5.
Sam writes an addition that she can solve using the known fact 5 + 4 = 9 The first addend and the sum both have 6 tens. What could her fact be?
65 + 5 = 70
64 + 4 = 68
63 + 4 = 67
Correct answer: 65 + 4 = 69
Q6.
What number did Sam subtract?
An image in a quiz
Correct Answer: 6, 6 ones, six

Exit quiz

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6 Questions

Q1.
Alex bought a cake for 34 p and a bag for 3 p. How much did he spend altogether? Which part-part-whole model represents the problem?
An image in a quiz
Correct Answer: An image in a quiz
An image in a quiz
Correct Answer: An image in a quiz
An image in a quiz
Q2.
Sam spent 37 p altogether on a box and a ribbon. The ribbon cost 3 p. How much did the box cost? Which known fact will help you solve the problem?
Correct answer: 7 - 3 = 4
4 - 3 = 1
3 + 1 = 4
Q3.
Choose the known fact that would help solve this problem. There were 54 cars in the car park. 3 were red. How many weren’t red?
4 - 1 = 3
1 + 3 = 4
Correct answer: 4 - 3 = 1
Q4.
Choose the known fact that would help solve this story. First, I had 75 books on the shelf. Then, 3 fell off. Now, how many books are on the shelf?
3 + 2 = 5
Correct answer: 5 - 3 = 2
5 - 2 = 3
Q5.
Sam’s sunflower was 86 cm tall and Alex’s sunflower was shorter. The difference between them was 4 cm. How tall was Sam’s sunflower. Write the known fact that would help you solve this problem.
Correct Answer: 6 - 4 = 2, 86 - 4 = 82
Q6.
Choose the known fact that would help solve this problem. Sam saved £45 and then she saved £4 more. How much money did she save altogether?
5 - 4 = 1
Correct answer: 5 + 4 = 9
9 - 5 = 4