# Add and subtract within 100 by applying related one-digit addition and subtraction facts: add and subtract only ones or only tens to/from a two-digit number (2)

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## Description

Pupils should be able to apply known one-digit additive facts to:

• adding and subtracting 2 multiples of ten (for example, 40 + 30 = 70 and 70 – 30 = 40)
• adding and subtracting ones to/from a two-digit number (for example, 64 + 3 = 67 and 67 – 3 = 64)
• adding and subtracting multiples of ten to/from a two-digit number (for example, 45 + 30 = 75 and 75 – 30 = 45)
• the special case of subtracting ones from a multiple of ten, by using complements of 10 (for example 30 – 3 = 27)

Tens frames, Dienes and partitioning diagrams can be used to support pupils as they learn how to relate these calculations to one-digit calculations.

Language focus

“4 plus 3 is equal to 7. So 4 tens and plus 3 tens is equal to 7 tens.”

“10 minus 3 is equal to 7. So 30 minus 3 is equal to 27.”

Pupils should also be able to apply strategies for addition or subtraction across 10, from above, to addition or subtraction bridging a multiple of 10. You can find out more about fluency and recording for all of these calculation types here in the calculation and fluency section: 2AS–3