Know that addition and subtraction are inverse operations
I can recognise addition and subtraction as the inverse of each other.
Know that addition and subtraction are inverse operations
I can recognise addition and subtraction as the inverse of each other.
Lesson details
Key learning points
- Addition is the inverse of subtraction. Addition can 'undo' subtraction.
- Subtraction is the inverse of addition. Subtraction can 'undo' addition.
- When a given amount is added to the start of a story, to 'undo' the change, we must subtract the same amount.
- When a given amount is subtracted from the start of a story, to 'undo' the change we must add the same amount.
Common misconception
Children may not understand the importance of the order of the numerals in equations, so may not understand that the amount added or subtracted is of key importance when undoing a change made.
Present errors to discuss and correct. Encourage children to use practical equipment to demonstrate how they know they are right or to show why an error made cannot be correct.
Keywords
Add - o find the total, or sum, by combining two or more parts (addends), or to increase an amount by adding another.
Subtract - To partition one part from another (the subtrahend from the difference), or to decrease an amount by taking an amount away.
Inverse - Inverse means the opposite in effect; the reverse of.
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).
Video
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Starter quiz
6 Questions
Exit quiz
6 Questions
7 − 3 = 4
6 − 1 = 5
3 − 3 = 0
