Subtraction strategies to four digits
"Taking away from the pile? Or finding the gap between two piles? Both are subtraction," says Biscuit. "And you can always check by adding your answer back."
1. Subtract.
a) 680 − 240 = b) 1 500 − 750 =
2. The friends had 4 000 gumnuts and shared 1 640 with the birds. How many are left? Show your working.
3. Subtract, then check by adding back.
a) 3 250 − 1 480 = Check:
4. Bo had 2 100 gumnuts and gave some away. He has 1 350 left. How many did he give away?
5. Challenge: Mae thinks 600 − 199 is easy if you take 200 then add 1 back. Try it, and explain why that works.