2-min Fluency Warm-up — Mental math.
53 + 10 =
78 − 10 =
200 + 100 =
400 − 100 =
Estimate First! Round to tens, estimate, then find the actual answer.
38 + 27
Estimate (40 + 30):
Actual:
65 − 28
Estimate (70 − 30):
Actual:
44 + 39
Estimate (40 + 40):
Actual:
82 − 36
Estimate (80 − 40):
Actual:
Use a different strategy for each problem.
Strategies: column method, base-10 blocks, number line, counting up.
28 + 45 =
Strategy I used:
73 − 38 =
Strategy I used:
56 + 37 =
Strategy I used:
91 − 45 =
Strategy I used:
Read carefully. Think about what is happening.
The art room had 36 paint brushes. The teacher ordered 27 more. Then 8 brushes broke and were thrown away. How many good brushes are there now?
Draw or write your thinking:
brushes
A train had 84 passengers at the first stop. At the second stop, 31 passengers got off. At the third stop, 19 passengers got on. How many passengers are on the train now?
Draw or write your thinking:
passengers
Number Talk — Explain WITHOUT calculating.
A: 45 + 38
B: 48 + 35
Which is bigger, or are they the same?
My thinking:
A: 72 − 24
B: 72 − 34
Which is bigger, or are they the same?
My thinking: