Add and subtract one to or from a two-digit number within a decade

I can add and subtract 1 to and from a 2-digit number within a decade.

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Year 2

Add and subtract one to or from a two-digit number within a decade

I can add and subtract 1 to and from a 2-digit number within a decade.

Download all resources

Share activities with pupils

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Lesson details

Key learning points

Finding one more is the same as adding 1. Finding one less is the same as subtracting 1
Numbers that are one more or one less than each other have a difference of one.

Keywords

One more - The number that is one more than another is the result of adding 1 to that number
One less - The number that is one less than another is the result of subtracting 1 from that number
Difference - The result of subtracting one number from another. How much one number differs from another.

Common misconception

The language of one more or one less than can confuse children, so 55 is one more than ? may be interpreted as 55 plus 1

Encourage children to articulate and explain in full sentences alongside number lines to support the understanding of the different ways to articulate the concept. Use stem sentences to support with this and display them around the classroom.

Avoid calculations which involve regrouping at this point. Use part-part-whole models to teach commutativity and inverse. Allow children the opportunity to explore these patterns with familiar representations such as number lines and base ten equipment.

Teacher tip

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).