2-min Fluency Warm-up — Subtract 10 in your head.
35 − 10 =
68 − 10 =
92 − 10 =
54 − 10 =
When you can't subtract the ones, break a ten: trade 1 ten for 10 ones.
Draw base-10 blocks. Show how you break a ten to subtract the ones.
53 - 17
Regroup 1 ten as 10 ones
72 - 28
Regroup 1 ten as 10 ones
Can you subtract the ones? If not, break a ten!
53 − 17 =
72 − 28 =
61 − 24 =
85 − 37 =
Number Talk — Explain WITHOUT calculating.
Which difference is bigger?
53 − 17 or 53 − 27
My thinking:
Which difference is bigger?
72 − 28 or 82 − 28
My thinking:
Challenge — Show two different ways to solve each problem.
Try: (1) breaking a ten with blocks, (2) counting up from the smaller number.
61 − 24 =
Strategy 1:
Strategy 2:
85 − 37 =
Strategy 1:
Strategy 2: