Add 2 and 3-digit numbers by redistributing
I can add 2 and 3-digit numbers by redistributing.
Add 2 and 3-digit numbers by redistributing
I can add 2 and 3-digit numbers by redistributing.
Lesson details
Key learning points
- If we subtract 1 from one addend, we must add one to the other added for the sum to remain the same
- When we redistribute, the total amount stays the same at all times
- Depending on the addends, we redistribute 1s or 10s
Common misconception
Pupils will sometimes remove or add ones or tens to one addend and forget to amend the other addend so that the calculation has been transformed but doesn't give the same sum as the original.
Encourage buddy checking of jottings as the children practise so that they can help each other to be reminded.
Keywords
Redistribute - Redistribution is a way of transforming a sum to make it easier to calculate mentally.
Inverse - The inverse is the opposite or reverse operation. For example, subtraction is the inverse operation of addition.
Efficient - Being efficient means finding a way to solve a problem quickly whilst also maintaining accuracy.
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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Starter quiz
6 Questions
Exit quiz
6 Questions
30 + 16
19 + 36
12 + 80
