Add and Subtract Decimals with Regrouping: Vertical - Math ... - Free Printable

Let’s solve each problem one by one. We’ll add or subtract the decimals carefully, making sure to line up the decimal points and regroup (carry or borrow) when needed.

---

Problem 1: 1.5 + 7.7

Line them up:

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

Add tenths: 5 + 7 = 12 → write down 2, carry over 1
Add ones: 1 + 7 + 1 (carry) = 9

Answer: 9.2

---

Problem 2: 13.9 + 51.58

Write 13.9 as 13.90 to match decimal places:

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

Hundredths: 0 + 8 = 8
Tenths: 9 + 5 = 14 → write 4, carry 1
Ones: 3 + 1 + 1 (carry) = 5
Tens: 1 + 5 = 6

Answer: 65.48

---

Problem 3: 49.68 - 28.689

Write 49.68 as 49.680:

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

Start from right:

Thousandths: 0 - 9 → can’t do, borrow → 10 - 9 = 1 (but we borrowed, so next digit becomes 7)

Hundredths: 7 (after borrow) - 8 → can’t do, borrow again → 17 - 8 = 9 (next digit becomes 5)

Tenths: 5 (after borrow) - 6 → can’t do, borrow → 15 - 6 = 9 (ones become 8)

Ones: 8 (after borrow) - 8 = 0
Tens: 4 - 2 = 2

Wait — let’s redo this more carefully with borrowing steps:

Actually, better to think:

49.680
-28.689
= ?

From right:

0 < 9 → borrow from 8 (hundredths place). But 8 is 8, so it becomes 7, and thousandths becomes 10.

10 - 9 = 1

Now hundredths: 7 - 8 → need to borrow from tenths (6). Tenths become 5, hundredths become 17.

17 - 8 = 9

Tenths: 5 - 6 → need to borrow from ones (9). Ones become 8, tenths become 15.

15 - 6 = 9

Ones: 8 - 8 = 0

Tens: 4 - 2 = 2

So result: 20.991

Wait — that doesn’t feel right. Let me check with calculator-style thinking:

49.680 minus 28.689:

Subtract whole numbers first: 49 - 28 = 21
But since 0.680 < 0.689, we actually have to borrow 1 from 21 → 20, and then 1.680 - 0.689 = 0.991

So total: 20 + 0.991 = 20.991

Yes, correct.

---

Problem 4: 2.6 + 5.7

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

6 + 7 = 13 → write 3, carry 1
2 + 5 + 1 = 8

Answer: 8.3

---

Problem 5: 74.8 + 10.57

Write 74.8 as 74.80

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

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

Answer: 85.37

---

Problem 6: 36.831 - 29.266

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

Thousandths: 1 - 6 → borrow → 11 - 6 = 5 (hundredths becomes 2)

Hundredths: 2 - 6 → borrow → 12 - 6 = 6 (tenths becomes 7)

Tenths: 7 - 2 = 5? Wait — original tenths was 8, we borrowed for hundredths, so now 7. Then subtract 2 → 5? No:

Wait, let's go step by step:

Start from right:

Thousandths: 1 < 6 → borrow from hundredths (3). Hundredths become 2, thousandths become 11.

11 - 6 = 5

Hundredths: 2 (after borrow) < 6 → borrow from tenths (8). Tenths become 7, hundredths become 12.

12 - 6 = 6

Tenths: 7 (after borrow) - 2 = 5

Ones: 6 - 9 → can't do → borrow from tens (3). Tens become 2, ones become 16.

16 - 9 = 7

Tens: 2 - 2 = 0

So answer: 7.565

Check: 29.266 + 7.565 = 36.831 → yes!

---

Problem 7: 1.49 + 4.78

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

Hundredths: 9 + 8 = 17 → write 7, carry 1
Tenths: 4 + 7 + 1 = 12 → write 2, carry 1
Ones: 1 + 4 + 1 = 6

Answer: 6.27

---

Problem 8: 93.10 - 12.401

Write 93.10 as 93.100

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

Thousandths: 0 - 1 → borrow → 10 - 1 = 9 (hundredths becomes 9)

Hundredths: 9 (after borrow) - 0 = 9? Wait — original hundredths was 0, we borrowed for thousandths, so it became 9? Actually:

Let’s break it:

Thousandths: 0 < 1 → borrow from hundredths. But hundredths is 0 → so borrow from tenths.

Tenths is 1 → becomes 0, hundredths become 10. Now borrow from hundredths for thousandths: hundredths become 9, thousandths become 10.

10 - 1 = 9

Hundredths: 9 - 0 = 9

Tenths: 0 (after borrow) - 4 → can’t do → borrow from ones (3). Ones become 2, tenths become 10.

10 - 4 = 6

Ones: 2 - 2 = 0

Tens: 9 - 1 = 8

Answer: 80.699

Check: 12.401 + 80.699 = 93.100 → yes!

---

Problem 9: 41.933 - 27.958

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

Thousandths: 3 - 8 → borrow → 13 - 8 = 5 (hundredths becomes 2)

Hundredths: 2 - 5 → borrow → 12 - 5 = 7 (tenths becomes 8)

Tenths: 8 - 9 → borrow → 18 - 9 = 9 (ones become 0)

Ones: 0 - 7 → borrow → 10 - 7 = 3 (tens become 3)

Tens: 3 - 2 = 1

Answer: 13.975

Check: 27.958 + 13.975 = 41.933 → yes!

---

Problem 10: 1.57 + 2.65

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

Hundredths: 7 + 5 = 12 → write 2, carry 1
Tenths: 5 + 6 + 1 = 12 → write 2, carry 1
Ones: 1 + 2 + 1 = 4

Answer: 4.22

---

Problem 11: 68.61 - 45.752

Write 68.61 as 68.610

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

Thousandths: 0 - 2 → borrow → 10 - 2 = 8 (hundredths becomes 0)

Hundredths: 0 - 5 → borrow → 10 - 5 = 5 (tenths becomes 5)

Tenths: 5 - 7 → borrow → 15 - 7 = 8 (ones become 7)

Ones: 7 - 5 = 2

Tens: 6 - 4 = 2

Answer: 22.858

Check: 45.752 + 22.858 = 68.610 → yes!

---

Problem 12: 80.915 - 78.398

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

Thousandths: 5 - 8 → borrow → 15 - 8 = 7 (hundredths becomes 0)

Hundredths: 0 - 9 → borrow → 10 - 9 = 1 (tenths becomes 8)

Tenths: 8 - 3 = 5? Wait — original tenths was 9, we borrowed for hundredths, so now 8. Subtract 3 → 5? No:

Wait, let’s do step by step:

Thousandths: 5 < 8 → borrow from hundredths (1). Hundredths become 0, thousandths become 15.

15 - 8 = 7

Hundredths: 0 < 9 → borrow from tenths (9). Tenths become 8, hundredths become 10.

10 - 9 = 1

Tenths: 8 - 3 = 5

Ones: 0 - 8 → can’t do → borrow from tens (8). Tens become 7, ones become 10.

10 - 8 = 2

Tens: 7 - 7 = 0

Answer: 2.517

Check: 78.398 + 2.517 = 80.915 → yes!

---

Final Answers:

1. 9.2
2. 65.48
3. 20.991
4. 8.3
5. 85.37
6. 7.565
7. 6.27
8. 80.699
9. 13.975
10. 4.22
11. 22.858
12. 2.517

──────────────────────────────────────

Final Answer:
9.2, 65.48, 20.991, 8.3, 85.37, 7.565, 6.27, 80.699, 13.975, 4.22, 22.858, 2.517