Starter quiz
- Which expression would give the same answer as 12 + 3 − 5?
- 10 − 5 + 3
- 12 − 5 + 3 ✓
- 12 − 3 + 5
-
- True or false? 16 + 4 – 2 is equal to 16 – 4 + 2
- True
- False ✓
- Match the expressions with those that have the same answer.
- 10 + 6 − 4⇔10 − 4 + 6 ✓
- 10 + 4 − 6⇔10 − 6 + 4 ✓
- 10 + 6 − 5⇔10 − 5 + 6 ✓
- What is 16 + 7 + 4 = ______
- '27' ✓
- There are 11 people on a bus. At the next stop, 4 people get on the bus and 2 people get off. How many people are on the bus? Which calculations would give the correct answer?
- 11 − 2 + 4 = ✓
- 11 + 2 − 4 =
- 11 + 4 − 2 = ✓
- 11 − 4 + 2 =
-
- What is the missing number? 15 + 5 − = 10
- '10' ✓
Exit quiz
- Which expression would give the same answer as 15 + 4 − 5?
- 15 − 4 + 5
- 5 − 5 + 4
- 15 − 5 + 4 ✓
-
- What is the most efficient order to answer 16 − 6 + 7?
- 16 − 6 + 7 ✓
- 16 + 7 − 6
- 16 + 6 − 7
-
- What is 17 − 8 + 3?
- 12 ✓
- 13
- 14
- 22
-
- What is 106 + 25 − 6 = ______
- '125' ✓
- What is 99 + 19 − 18?
- 100 ✓
- 101
- 109
- 118
-
- What is 187 − 30 + 40 = ______
- '197' ✓
Worksheet
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Presentation
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Video
Lesson Details
Key learning points
- Addition and subtraction can be done in any order
- If you do the addition and subtraction in a different order, the answer will be the same
- The most efficient order can be chosen by looking at the numbers
Common misconception
Pupils may struggle when reordering equations where the addends and subtrahends are calculated first (e.g. 455 + 39 - 38)
Give pupils opportunities to explore the relationship between the addend and subtrahend. They could calculate the answers to problems where the subtrahend is one less than the addend (e.g. 45 + 10 - 9). Can they see a pattern in their answers?
Keywords
Efficient - Working efficiently means finding a way to solve a problem quickly whilst also maintaining accuracy.
Reorder - Reorder means arrange something in a different way.
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