Mathematics
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3 quick questions from earlier weeks · about 3 minutes
- 15 − 7 = ? Facts to 20
- 94 − 25 = ? Week 7
- Write 900 + 20 + 3 as one number. Week 5
Objective: Students add three two-digit numbers by looking for pairs that make a ten or a friendly number (2.NBT.B.6).
- 10 min — Warm-Up: Revisit any circled problems from last Friday's assessment. Then play 'find the ten': say three one-digit numbers (7, 5, 3) and your child names the pair that makes ten and the total (7 + 3 = 10, plus 5 = 15). Try 6, 8, 2 and 4, 9, 6 and 5, 5, 8.
- 15 min — Mini-Lesson: Write 23 + 47 + 15 vertically. Point to the ones column: 3, 7, 5. Say, '3 and 7 make a ten, then 5 more is 15.' Write the 5, carry the ten to the tens column as one straw bundle, and add 2 + 4 + 1 + 1 = 8 tens: 85. Repeat with 36 + 28 + 14 (6 + 4 makes ten, total 78), building tens with straws each time.
- 15 min — Practice: Your child solves 12 + 38 + 25, 41 + 19 + 27, 33 + 33 + 17, and 26 + 54 + 15, circling the pair of ones that makes a ten before adding (answers 75, 87, 83, 95). Build the third problem with straws to prove it.
- 5 min — Wrap-Up: Ask, 'Does it matter which two numbers you add first?' Test it together on 12 + 38 + 25 by adding 12 + 25 first, then 38 (still 75).
Materials: paper, pencil, straws bundled by ten, loose straws