Add & Subtract

Addition and subtraction, in your head

Addition and subtraction you do out loud, with somebody else in the room. The questions start at 2 + 2 and end at “You have 240, spend 85, then get 50 back” — and in between they teach the moves rather than drill the facts. 47 + 8 becomes bridging to the next ten. 46 + 38 becomes decomposing into tens and ones. Subtracting becomes counting up, which finds the difference with no borrowing at all.

Every strategy is named the way a Canadian classroom names it — making ten, near doubles, compensation, decomposing — so a child hears the same word at the table that they hear at school, and the adult playing picks up the vocabulary too.