Extend understanding of the operations addition and subtraction. Use and begin to read the related vocabulary. Use the +, − and = signs to record mental additions and subtractions in a number sentence, and recognise the use of a symbol to stand for an unknown number. Recognise that addition can be done in any order but not subtraction.
se knowledge that addition can be done in any order to do mental calculations more efficiently. For example: put the larger number first and count on in tens or ones.
Add/subtract 9 or 11: add/subtract 10 and adjust by 1.
Explain how a problem was solved orally and, where appropriate in writing.