# Use knowledge of addition and subtraction facts within 10 to add and subtract within 20

I can use knowledge of addition and subtraction facts within 10 to add and subtract within 20

# Use knowledge of addition and subtraction facts within 10 to add and subtract within 20

I can use knowledge of addition and subtraction facts within 10 to add and subtract within 20

## Slide deck

## Lesson details

### Key learning points

- Addition facts within ten can be applied to addition within 20
- Subtraction facts within ten can be applied to subtraction within 20
- If 3 + 2 is equal to 5 then 13 + 2 is equal to 15
- If 5 - 2 is equal to 3 then 15 - 2 is equal to 13

### Common misconception

Children may rely on counting strategies instead of using known facts to add or subtract from larger numbers.

Make comparisons between addition and subtraction within 10 and within 20, looking for patterns. Make sure children notice that the ones digit stays the same when we add and subtract numbers with the same ones digits such as 5 - 2 and 15 - 2

### Keywords

Addition - To find the total, or sum, by combining two or more parts (addends), or to increase an amount by adding another.

Subtraction - To partition one part from another (the subtrahend from the difference), or to decrease an amount by taking an amount away.

Plus - A synonym for add, represented by the symbol +

Minus - A synonym for add, represented by the symbol -

### 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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