Let's solve the addition problems on this worksheet step by step and then answer the key question.
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Worksheet: ADDITION – ADDING ON TENS SHEET 1
We are adding multiples of 10 to two-digit numbers. The goal is to understand how adding tens affects the number.
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Solutions:
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Problems 1–15 (Left Column):
1) 35 + 10 =
45
2) 52 + 10 =
62
3) 67 + 10 =
77
4) 58 + 10 =
68
5) 75 + 20 =
95
6) 66 + 20 =
86
7) 51 + 20 =
71
8) 38 + 20 =
58
9) 25 + 30 =
55
10) 42 + 30 =
72
11) 37 + 20 =
57
12) 68 + 10 =
78
13) 39 + 30 =
69
14) 45 + 20 =
65
15) 56 + 30 =
86
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Problems 16–30 (Right Column):
16) 27 + 30 =
57
17) 56 + 30 =
86
18) 75 + 20 =
95
19) 19 + 40 =
59
20) 55 + 30 =
85
21) 14 + 40 =
54
22) 28 + 50 =
78
23) 16 + 60 =
76
24) 39 + 50 =
89
25) 72 + 20 =
92
26) 56 + 40 =
96
27) 38 + 30 =
68
28) 65 + 40 =
105
29) 29 + 70 =
99
30) 43 + 60 =
103
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Key Question: What happens to the ones digit when you add on tens?
✔ Answer:
When you add tens (like 10, 20, 30, etc.) to a number,
the ones digit stays the same.
Explanation:
Adding tens only changes the
tens place of the number. The
ones digit remains unchanged because you're not adding anything to the ones place.
For example:
- 35 + 10 = 45 → ones digit is still
5
- 52 + 10 = 62 → ones digit is still
2
- 29 + 70 = 99 → ones digit is still
9
Even in cases like 65 + 40 = 105, the ones digit is still
5.
So,
adding tens does not change the ones digit — it only increases the tens digit.
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✔ Final Answer to Key Question:
>
The ones digit stays the same when you add on tens.
This concept helps students understand place value and builds mental math skills.
Parent Tip: Review the logic above to help your child master the concept of math worksheet mental addition subtraction.
