This Grade 2 worksheet teaches the build-back-to-ten strategy for addition within 100. Nine fill-in items walk second graders through splitting a second addend so the sum first lands on a friendly ten, like 35 plus 5 to reach 40, then 3 more. A four-item matching section pairs problems with their correct split steps, helping Grade 2 students make tens automatically and add across decades with confidence.
Style:
Mental Math Within 100
Part A: Fill in the Blank
Write the missing word or number on each line.
1. 35 + 8: first add 5 to reach 40, then 3 more. Sum is 43.
2. 28 + 7 = 28 + 2 + 5, which equals 35.
3. 47 + 6 = 47 + 3 + 3 = 53.
4. To solve 69 + 5, first add 1 to reach 70.
5. 69 + 5 = 69 + 1 + 4 = 74.
6. 56 + 9 = 56 + 4 + 5, which gives 65.
7. 72 + 8 uses 8 = 8 + 0 because 72 + 8 already lands on a ten.
8. 48 + 7 = 48 + 2 + 5 to finish the make-a-ten step.
9. 29 + 6 = 29 + 1 + 5 = 35.
Part B: Matching
Match each item on the left to the correct answer on the right.
1. Match each item to its correct answer.
38 + 5
→ 38 + 2 + 3
38 + 2 + 3
46 + 7
→ 46 + 4 + 3
46 + 4 + 3
59 + 4
→ 59 + 1 + 3
59 + 1 + 3
27 + 6
→ 27 + 3 + 3
27 + 3 + 3
Mental Math Within 100
★ Part A: Fill in the Blank
Write the missing word or number on each line.
1) 35 + 8: first add 5 to reach 40, then 3 more. Sum is 43.
2) 28 + 7 = 28 + 2 + 5, which equals 35.
3) 47 + 6 = 47 + 3 + 3 = 53.
4) To solve 69 + 5, first add 1 to reach 70.
5) 69 + 5 = 69 + 1 + 4 = 74.
6) 56 + 9 = 56 + 4 + 5, which gives 65.
7) 72 + 8 uses 8 = 8 + 0 because 72 + 8 already lands on a ten.
8) 48 + 7 = 48 + 2 + 5 to finish the make-a-ten step.
9) 29 + 6 = 29 + 1 + 5 = 35.
★ Part B: Matching
Match each item on the left to the correct answer on the right.
1) Match each item to its correct answer.
38 + 5
→ 38 + 2 + 3
38 + 2 + 3
46 + 7
→ 46 + 4 + 3
46 + 4 + 3
59 + 4
→ 59 + 1 + 3
59 + 1 + 3
27 + 6
→ 27 + 3 + 3
27 + 3 + 3
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10 Questions
10-15 minutes
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