Counting by 10s | 1st grade, 2nd grade Math Worksheet | GreatSchools - Free Printable

Let's solve the "Counting by 10s" worksheet step by step. The goal is to fill in the missing numbers in each row, counting by 10s (i.e., increasing by 10 each time).

---

🔢 Rule: Count by 10s

This means each number increases by 10 from the previous one. For example:
10, 20, 30, 40, 50, 60, 70, 80, 90, 100

We’ll use this pattern to fill in the blanks.

---

✔ Problem 1:

```
10 | 20 | ___ | ___ | 50 | ___ | ___ | 80
```

- Start at 10 → 20 → next should be 30, then 40, then 50 (given), then 60, 70, then 80.
- So the missing numbers are: 30, 40, 60, 70

✔ Answer: 30, 40, 60, 70

---

✔ Problem 2:

```
20 | ___ | 40 | 50 | ___ | 70 | ___ | ___
```

- 20 → next is 30, then 40 (given), 50 (given), then 60, 70 (given), then 80, 90
- Missing: 30, 60, 80, 90

✔ Answer: 30, 60, 80, 90

---

✔ Problem 3:

```
30 | 40 | ___ | ___ | 70 | ___ | ___ | 100
```

- 30 → 40 → 50, 60, 70 (given) → 80, 90, 100 (given)
- Missing: 50, 60, 80, 90

✔ Answer: 50, 60, 80, 90

---

✔ Problem 4:

```
___ | 20 | ___ | ___ | 50 | ___ | ___ | 80
```

- First number before 20 must be 10 (since we're counting by 10s)
- Then: 10 → 20 → 30, 40, 50 (given) → 60, 70, 80 (given)
- Missing: 10, 30, 40, 60, 70

✔ Answer: 10, 30, 40, 60, 70

---

✔ Problem 5:

```
___ | 30 | ___ | 50 | ___ | ___ | 80 | ___
```

- Before 30 → 20
- After 30 → 40, then 50 (given), then 60, 70, 80 (given), then 90
- Missing: 20, 40, 60, 70, 90

✔ Answer: 20, 40, 60, 70, 90

---

✔ Problem 6:

```
30 | ___ | ___ | ___ | 70 | ___ | ___ | 100
```

- 30 → 40, 50, 60, 70 (given) → 80, 90, 100 (given)
- Missing: 40, 50, 60, 80, 90

✔ Answer: 40, 50, 60, 80, 90

---

✔ Problem 7:

```
___ | 30 | ___ | ___ | ___ | ___ | 80 | ___
```

- Before 30 → 20
- Then: 20 → 30 → 40, 50, 60, 70, 80 (given) → 90
- Missing: 20, 40, 50, 60, 70, 90

✔ Answer: 20, 40, 50, 60, 70, 90

---

✔ Problem 8:

```
___ | ___ | 50 | ___ | ___ | ___ | 90 | ___
```

- Before 50 → 40, then 30, then 20, 10
- But order is: first blank, second blank, then 50 → so let’s go forward:
- 50 → 60, 70, 80, 90 (given) → 100
- So sequence: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100
- We have: ___, ___, 50, ___, ___, ___, 90, ___
- So positions:
- 1st: 30
- 2nd: 40
- 3rd: 50 (given)
- 4th: 60
- 5th: 70
- 6th: 80
- 7th: 90 (given)
- 8th: 100

Wait — that can’t be right because there are only 8 boxes and we’re starting at 30?

Let’s count:

Boxes:
1) ___
2) ___
3) 50
4) ___
5) ___
6) ___
7) 90
8) ___

So the sequence must go:
Let’s suppose it starts at 30 → then 40 → 50 → 60 → 70 → 80 → 90 → 100

But box 1 = 30, box 2 = 40, box 3 = 50, box 4 = 60, box 5 = 70, box 6 = 80, box 7 = 90, box 8 = 100

That works!

So missing numbers:
Box 1: 30
Box 2: 40
Box 4: 60
Box 5: 70
Box 6: 80
Box 8: 100

✔ Answer: 30, 40, 60, 70, 80, 100

---

✔ Final Answers:

1) 30, 40, 60, 70
2) 30, 60, 80, 90
3) 50, 60, 80, 90
4) 10, 30, 40, 60, 70
5) 20, 40, 60, 70, 90
6) 40, 50, 60, 80, 90
7) 20, 40, 50, 60, 70, 90
8) 30, 40, 60, 70, 80, 100

---

📝 Summary:

All sequences follow the pattern of counting by 10s. By identifying the known numbers and filling in the gaps with +10 steps, we complete each row.

Let me know if you'd like a printable version or visual explanation!