Flip the whole is a game to consolidate the subtraction using doubles strategy. It's a good game to show the link between addition and subtraction and to practice efficient mental strategies.
How to Play:
Students play individually or in teams of 2, 3 or 4. Flip the number card (this is the whole) and record the subtraction number sentence using doubles. Eg: if you flipped a 20 then you would record 20 - 10 = 10.