Let’s solve each problem step by step. We’ll go one at a time, carefully checking our work.
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1. 23 + 20 = ?
23 + 20 → add tens: 20 + 20 = 40, then +3 →
43
2. 75 - 25 = ?
75 - 25 → subtract tens: 70 - 20 = 50, then 5 - 5 = 0 →
50
3. 48 + 68 = ?
48 + 68 → break it down:
40 + 60 = 100
8 + 8 = 16
100 + 16 =
116
4. 70 - 29 = ?
70 - 29 → think: 70 - 30 = 40, but we subtracted 1 too many → so add 1 back →
41
5. 54 - 15 = ?
54 - 15 → 54 - 10 = 44, then 44 - 5 =
39
6. 24 + 69 = ?
24 + 69 → 20 + 60 = 80, 4 + 9 = 13 → 80 + 13 =
93
7. 80 - 47 = ?
80 - 47 → 80 - 40 = 40, then 40 - 7 =
33
8. 45 + 34 = ?
45 + 34 → 40 + 30 = 70, 5 + 4 = 9 →
79
9. 38 + 97 = ?
38 + 97 → 30 + 90 = 120, 8 + 7 = 15 → 120 + 15 =
135
10. 63 + 10 = ?
Easy! Just add 10 to 63 →
73
11. 81 - 52 = ?
81 - 52 → 81 - 50 = 31, then 31 - 2 =
29
12. 95 - 48 = ?
95 - 48 → 95 - 50 = 45, but we subtracted 2 too many → add 2 back →
47
13. 60 - 35 = ?
60 - 35 → 60 - 30 = 30, then 30 - 5 =
25
14. 34 + 19 = ?
34 + 19 → 34 + 20 = 54, minus 1 →
53
15. 39 - 17 = ?
39 - 17 → 39 - 10 = 29, then 29 - 7 =
22
16. 34 + 64 = ?
34 + 64 → 30 + 60 = 90, 4 + 4 = 8 →
98
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Now let’s double-check a few that might be tricky:
- #3: 48 + 68 → 48 + 60 = 108, +8 = 116
✔
- #4: 70 - 29 → 29 + 41 = 70? 29 + 40 = 69, +1 = 70 → yes, 41
✔
- #7: 80 - 47 → 47 + 33 = 80? 47 + 30 = 77, +3 = 80 → yes
✔
- #9: 38 + 97 → 38 + 100 = 138, minus 3 = 135
✔
- #12: 95 - 48 → 48 + 47 = 95? 48 + 40 = 88, +7 = 95 → yes
✔
All look correct!
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Final Answer:
43
50
116
41
39
93
33
79
135
73
29
47
25
53
22
98
Parent Tip: Review the logic above to help your child master the concept of open number line subtraction worksheet.
