Printable math worksheet for practicing decimal addition and subtraction with regrouping.

Let's solve each of the decimal addition and subtraction problems step by step, with regrouping where necessary.

---

1. 1.5 + 7.7

```
1.5
+ 7.7
-----
9.2
```

Explanation:
Add the tenths: 5 + 7 = 12 → write down 2, carry over 1 to the ones place.
Add the ones: 1 + 7 = 8, plus the carried 1 = 9.
Result: 9.2

---

2. 13.9 + 51.58

Align decimals:

```
13.90
+ 51.58
-------
65.48
```

Explanation:
Convert 13.9 to 13.90 for easier alignment.
Add hundredths: 0 + 8 = 8
Tenths: 9 + 5 = 14 → write 4, carry 1
Ones: 3 + 1 = 4, plus carry = 5
Tens: 1 + 5 = 6
Result: 65.48

---

3. 49.68 - 28.689

Align decimals (add a zero):

```
49.680
- 28.689
--------
20.991
```

Explanation:
Borrow from the left when needed.
Start from right:
- 0 - 9 → can't do → borrow → 10 - 9 = 1, but next digit is 8 → becomes 7 after borrowing.
- 7 - 8 → can't → borrow → 17 - 8 = 9, previous becomes 5.
- 5 - 6 → can't → borrow → 15 - 6 = 9, previous becomes 8.
- 8 - 8 = 0
- 9 - 2 = 7? Wait — let's go step by step.

Actually, better:

```
49.680
- 28.689
--------
```

From right:
- 0 - 9 → borrow → 10 - 9 = 1, 8 becomes 7
- 7 - 8 → borrow → 17 - 8 = 9, 6 becomes 5
- 5 - 6 → borrow → 15 - 6 = 9, 9 becomes 8
- 8 - 8 = 0
- 4 - 2 = 2

Wait — tens: 4 (from 49) minus 2 (from 28) = 2
But we had 49.680 → 4 tens, 9 ones

After borrowing:
- Ones: 9 → became 8 after borrow
- So: 8 - 8 = 0
- Tens: 4 - 2 = 2

So result: 20.991

✔ Correct.

---

4. 2.6 + 5.7

```
2.6
+ 5.7
-----
8.3
```

Explanation:
6 + 7 = 13 → write 3, carry 1
2 + 5 = 7, plus carry = 8
Result: 8.3

---

5. 74.8 + 10.57

Align:

```
74.80
+ 10.57
-------
85.37
```

Explanation:
Hundredths: 0 + 7 = 7
Tenths: 8 + 5 = 13 → write 3, carry 1
Ones: 4 + 0 = 4, plus carry = 5
Tens: 7 + 1 = 8
Result: 85.37

---

6. 36.831 - 29.266

```
36.831
- 29.266
--------
7.565
```

Step-by-step:
- Thousandths: 1 - 6 → borrow → 11 - 6 = 5, 3 becomes 2
- Hundredths: 2 - 6 → borrow → 12 - 6 = 6, 8 becomes 7
- Tenths: 7 - 2 = 5
- Ones: 6 - 9 → borrow → 16 - 9 = 7, 3 becomes 2
- Tens: 2 - 2 = 0

Wait: original number is 36.831 → so tens digit is 3, ones is 6

After borrowing:
- Ones: 6 → becomes 5 after borrow? Let's recheck:

Better:
```
36.831
-29.266
-------
```

Start from right:
- 1 - 6 → borrow → 11 - 6 = 5 → 3 becomes 2
- 2 - 6 → borrow → 12 - 6 = 6 → 8 becomes 7
- 7 - 2 = 5
- 6 - 9 → borrow → 16 - 9 = 7 → 3 becomes 2
- 2 - 2 = 0

So result: 7.565

✔ Yes.

---

7. 1.49 + 4.78

```
1.49
+ 4.78
------
6.27
```

Explanation:
- 9 + 8 = 17 → write 7, carry 1
- 4 + 7 = 11, plus carry = 12 → write 2, carry 1
- 1 + 4 = 5, plus carry = 6
Result: 6.27

---

8. 93.10 - 12.401

Align:

```
93.100
- 12.401
--------
80.699
```

Step-by-step:
- Thousandths: 0 - 1 → borrow → 10 - 1 = 9 → 0 becomes 9 after borrow?
Wait:

```
93.100
- 12.401
--------
```

Rightmost:
- 0 - 1 → borrow → 10 - 1 = 9 → 0 becomes 9 (but borrowed from left)
- But next digit is 0 → need to keep borrowing.

So:
- Thousandths: 0 - 1 → borrow → 10 - 1 = 9 → now 0 becomes 9, but it was already 0 → must go further.

Breakdown:
- Start from thousandths: 0 - 1 → can’t → borrow from hundredths
- But hundredths is 0 → so go to tenths: 1 → becomes 0, then hundredths gets 10
- Then hundredths gives 1 to thousandths → so thousandths becomes 10
- Now: 10 - 1 = 9
- Hundredths: now 9 (after giving 1), but subtract 0 → 9 - 0 = 9
- Tenths: 0 (after lending) - 4 → can’t → borrow from ones
- Ones: 3 → becomes 2, tenths get 10 → 10 - 4 = 6
- Ones: 2 - 2 = 0
- Tens: 9 - 1 = 8

Wait — original number: 93.100 → tens: 9, ones: 3

After:
- Tens: 9 - 1 = 8
- Ones: 3 → lent to tenths → becomes 2, then subtract 2 → 2 - 2 = 0
- Tenths: 1 → became 0, then got 10 → 10 - 4 = 6
- Hundredths: 0 → got 10, gave 1 → 9 - 0 = 9
- Thousandths: 10 - 1 = 9

So result: 80.699

✔ Correct.

---

9. 41.933 - 27.958

```
41.933
- 27.958
--------
13.975
```

Step-by-step:
- Thousandths: 3 - 8 → borrow → 13 - 8 = 5 → 3 becomes 2
- Hundredths: 2 - 5 → borrow → 12 - 5 = 7 → 9 becomes 8
- Tenths: 8 - 9 → borrow → 18 - 9 = 9 → 1 becomes 0
- Ones: 0 - 7 → borrow → 10 - 7 = 3 → 4 becomes 3
- Tens: 3 - 2 = 1

Wait: original tens: 4 (from 41), ones: 1

After:
- Tens: 4 → becomes 3 after borrow
- Ones: 1 → becomes 10 after borrow, then 10 - 7 = 3? No — we are subtracting 7 from ones?

Wait: subtracting 27.958 → so ones digit is 7

But after borrowing:
- Ones: 1 → becomes 0 after lending to tenths
- Then we need to borrow from tens → tens: 4 → becomes 3
- Ones: 10 → then subtract 7 → 3

Tenths: 9 → became 8 after lending to hundredths → then 8 - 9 → need to borrow → 18 - 9 = 9

Hundredths: 3 → became 2 after lending → then 2 - 5 → borrow → 12 - 5 = 7

Thousandths: 3 - 8 → borrow → 13 - 8 = 5

So final:
- Tens: 3 - 2 = 1
- Ones: 3
- Tenths: 9
- Hundredths: 7
- Thousandths: 5

→ 13.975

✔ Correct.

---

10. 1.57 + 2.65

```
1.57
+ 2.65
------
4.22
```

- 7 + 5 = 12 → write 2, carry 1
- 5 + 6 = 11, plus carry = 12 → write 2, carry 1
- 1 + 2 = 3, plus carry = 4
Result: 4.22

---

11. 68.61 - 45.752

Align:

```
68.610
- 45.752
--------
22.858
```

Step-by-step:
- Thousandths: 0 - 2 → borrow → 10 - 2 = 8 → 1 becomes 0
- Hundredths: 0 - 5 → borrow → 10 - 5 = 5 → 6 becomes 5
- Tenths: 5 - 7 → borrow → 15 - 7 = 8 → 8 becomes 7
- Ones: 7 - 5 = 2 → wait: original ones: 8 → became 7 after borrow → 7 - 5 = 2
- Tens: 6 - 4 = 2

Wait:
- Original: 68.610 → tens: 6, ones: 8
- After borrowing:
- Tenths: 6 → became 5 after lending to hundredths
- But we need to subtract 7 in tenths → so 5 → borrow from ones
- Ones: 8 → becomes 7
- Tenths: 15 - 7 = 8
- Then hundredths: 1 → became 0 after lending → now 0 - 5 → borrow → 10 - 5 = 5 → 6 becomes 5
- Thousandths: 0 → became 10 → 10 - 2 = 8

So:
- Tens: 6 - 4 = 2
- Ones: 7 - 5 = 2
- Tenths: 8
- Hundredths: 5
- Thousandths: 8

→ 22.858

✔ Correct.

---

12. 80.915 - 78.398

```
80.915
- 78.398
--------
2.517
```

Step-by-step:
- Thousandths: 5 - 8 → borrow → 15 - 8 = 7 → 1 becomes 0
- Hundredths: 0 - 9 → borrow → 10 - 9 = 1 → 9 becomes 8
- Tenths: 8 - 3 = 5
- Ones: 0 - 8 → can't → borrow from tens
- Tens: 8 → becomes 7, ones: 10 → 10 - 8 = 2
- Tens: 7 - 7 = 0

So:
- Tens: 0
- Ones: 2
- Tenths: 5
- Hundredths: 1
- Thousandths: 7

→ 2.517

✔ Correct.

---

## ✔ Final Answers:

| Problem | Answer |
|--------|--------|
| 1.5 + 7.7 | 9.2 |
| 13.9 + 51.58 | 65.48 |
| 49.68 - 28.689 | 20.991 |
| 2.6 + 5.7 | 8.3 |
| 74.8 + 10.57 | 85.37 |
| 36.831 - 29.266 | 7.565 |
| 1.49 + 4.78 | 6.27 |
| 93.10 - 12.401 | 80.699 |
| 41.933 - 27.958 | 13.975 |
| 1.57 + 2.65 | 4.22 |
| 68.61 - 45.752 | 22.858 |
| 80.915 - 78.398 | 2.517 |

---

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