Let’s solve each problem one by one. We’re adding two numbers in columns, and sometimes one number is missing — we need to find it so the total (sum) at the bottom is correct. No regrouping means we don’t carry over any tens — just add straight down.
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Problem 1:
54 + ? = 54 → The missing number must be
0, because 54 + 0 = 54.
Problem 2:
66 + 1 = ? → 66 + 1 =
67
Problem 3:
35 + 2 = ? → 35 + 2 =
37
Problem 4:
17 + ? = 18 → What do you add to 17 to get 18? That’s
1
Problem 5:
80 + 8 = ? → 80 + 8 =
88
Problem 6:
4 + 1 = ? → 4 + 1 =
5
Problem 7:
? + 1 = 72 → So the missing number is 72 - 1 =
71
Problem 8:
? + 5 = 7 → Missing number is 7 - 5 =
2
Problem 9:
? + 1 = 31 → Missing number is 31 - 1 =
30
Problem 10:
? + 7 = 28 → Missing number is 28 - 7 =
21
Problem 11:
75 + ? = 78 → Missing number is 78 - 75 =
3
Problem 12:
34 + ? = 37 → Missing number is 37 - 34 =
3
Problem 13:
72 + ? = 74 → Missing number is 74 - 72 =
2
Problem 14:
42 + 3 = ? → 42 + 3 =
45
Problem 15:
19 + 0 = ? → 19 + 0 =
19
Problem 16:
? + 1 = 46 → Missing number is 46 - 1 =
45
Problem 17:
? + 0 = 17 → Missing number is 17 - 0 =
17
Problem 18:
12 + ? = 17 → Missing number is 17 - 12 =
5
Problem 19:
20 + ? = 28 → Missing number is 28 - 20 =
8
Problem 20:
64 + 2 = ? → 64 + 2 =
66
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Final Answer:
1) 0
2) 67
3) 37
4) 1
5) 88
6) 5
7) 71
8) 2
9) 30
10) 21
11) 3
12) 3
13) 2
14) 45
15) 19
16) 45
17) 17
18) 5
19) 8
20) 66
Parent Tip: Review the logic above to help your child master the concept of worksheet work math.
