Starter quiz
- Which number in this equation is the sum? 18 + 8 = 26
- 8
- 18
- 26 ✓
-
- Which number is this equation is the minuend? 43 − 10 = 33
- 43 ✓
- 33
- 10
-
- Calculate the missing number in this equation: ______ − 14 = 10
- '24' ✓
- Calculate the missing number in this equation: 35 − ______ = 25
- '10' ✓
- What is the difference between 40 and 140?
- '100' ✓
- Calculate the missing number in this equation: ______ = 71 − 11
- '60' ✓
Exit quiz
- Which of these are equations?
- 24 + 10 = 34 ✓
- 96 − 20 = 76 ✓
- 5 + 5 + 10
- 10 + 5 = 5 + 10 ✓
-
- The equation 16 + 20 = 36 has been rearranged in different ways. Match up the parts of the equations to make them correct.
- 20 =⇔36 − 16 ✓
- 36 =⇔20 + 16 ✓
- 16 =⇔36 − 20 ✓
- Find the missing part. 20 + = 110
- 70
- 80
- 90 ✓
- 100
-
- What is the missing number? 65 = − 30
- '95' ✓
- There are some cherries in a bowl. Polly eats 12 cherries. There are 21 left. How many cherries were in the bowl to start with?
- 9
- 23
- 33 ✓
-
- There are 45 cherries in a bowl. Petra eats some cherries. There are 15 left. How many cherries did Petra eat?
- '30' ✓
Worksheet
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Presentation
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Video
Lesson Details
Key learning points
- When a whole is missing, add the parts together.
- To find a missing part, subtract the other part from the whole.
- Rearrange the equation to make it easier to calculate the missing number.
Common misconception
Pupils may use the wrong operation to find missing numbers, adding when they should be subtracting or vice versa.
Encourage pupils to draw bar models, focusing on the whole in the problem. They should also write problems, understanding where the missing number is and rearranging equations so that they can calculate the answers.
Keywords
Equation - An equation shows that one number or calculation is equal to another.
Rearrange - Rearrange means to change an equation. It could mean moving the parts or the whole or changing it from an addition into a subtraction equation.
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