Adding and Subtracting Decimals Worksheets - Math Monks - Free Printable
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Step-by-step solution for: Adding and Subtracting Decimals Worksheets - Math Monks
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Show Answer Key & Explanations
Step-by-step solution for: Adding and Subtracting Decimals Worksheets - Math Monks
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 work from right to left (thousandths place first).
---
① 3.897 + 1.127
Add thousandths: 7 + 7 = 14 → write 4, carry 1
Hundredths: 9 + 2 + 1 = 12 → write 2, carry 1
Tenths: 8 + 1 + 1 = 10 → write 0, carry 1
Ones: 3 + 1 + 1 = 5
→ 5.024
---
② 9.387 - 1.819
Thousandths: 7 - 9 → can’t do, borrow → 17 - 9 = 8
Hundredths: 8 becomes 7 (after borrow) → 7 - 1 = 6
Tenths: 3 - 8 → can’t do, borrow → 13 - 8 = 5
Ones: 9 becomes 8 → 8 - 1 = 7
→ 7.568
Wait — let me double-check that subtraction:
Actually, better to align:
```
9.387
- 1.819
-------
```
Start from right:
7 - 9 → borrow → 17 - 9 = 8
8 becomes 7 → 7 - 1 = 6
3 becomes 2 (because we borrowed for tenths? Wait no — actually, when we borrowed for thousandths, hundredths digit was reduced by 1. Then for tenths: 3 - 8 → need to borrow from ones.
So:
Ones: 9 → becomes 8 after lending to tenths
Tenths: 3 becomes 13 → 13 - 8 = 5
Hundredths: 8 became 7 (from earlier borrow) → 7 - 1 = 6
Thousandths: 7 became 17 → 17 - 9 = 8
Yes → 7.568
But wait — 9.387 minus 1.819 should be less than 8? Let me calculate numerically:
9.387 - 1.819 = ?
Do 9.387 - 1 = 8.387
Then 8.387 - 0.8 = 7.587
Then 7.587 - 0.019 = 7.568 → yes, correct.
---
③ 1.944 - 1.174
Thousandths: 4 - 4 = 0
Hundredths: 4 - 7 → borrow → 14 - 7 = 7
Tenths: 9 becomes 8 → 8 - 1 = 7
Ones: 1 - 1 = 0
→ 0.770 → which is 0.77
But since it's to thousandths, keep as 0.770
Actually, 1.944 - 1.174:
= (1.944 - 1.000) = 0.944
Then 0.944 - 0.174 = 0.770 → yes.
---
④ 5.234 + 4.199
Thousandths: 4 + 9 = 13 → write 3, carry 1
Hundredths: 3 + 9 + 1 = 13 → write 3, carry 1
Tenths: 2 + 1 + 1 = 4
Ones: 5 + 4 = 9
→ 9.433
Check: 5.234 + 4.199 = 5.234 + 4 + 0.199 = 9.234 + 0.199 = 9.433 → correct.
---
⑤ 3.092 - 1.308
Thousandths: 2 - 8 → borrow → 12 - 8 = 4
Hundredths: 9 becomes 8 → 8 - 0 = 8
Tenths: 0 - 3 → borrow → 10 - 3 = 7 (but ones digit will reduce)
Ones: 3 becomes 2 → 2 - 1 = 1
→ 1.784
Check: 3.092 - 1.308 = ?
3.092 - 1 = 2.092
2.092 - 0.3 = 1.792
1.792 - 0.008 = 1.784 → correct.
---
⑥ 4.448 - 3.432
Thousandths: 8 - 2 = 6
Hundredths: 4 - 3 = 1
Tenths: 4 - 4 = 0
Ones: 4 - 3 = 1
→ 1.016
Easy check: 4.448 - 3.432 = 1.016 → correct.
---
⑦ 9.423 + 3.231
Thousandths: 3 + 1 = 4
Hundredths: 2 + 3 = 5
Tenths: 4 + 2 = 6
Ones: 9 + 3 = 12
→ 12.654
Correct.
---
⑧ 4.982 - 2.999
This is tricky. Think of it as 4.982 - 3 + 0.001 = 1.982 + 0.001 = 1.983
Or step by step:
Thousandths: 2 - 9 → borrow → 12 - 9 = 3
Hundredths: 8 becomes 7 → 7 - 9 → borrow → 17 - 9 = 8
Tenths: 9 becomes 8 → 8 - 9 → borrow → 18 - 9 = 9
Ones: 4 becomes 3 → 3 - 2 = 1
→ 1.983
Yes.
---
⑨ 7.224 + 6.331
Thousandths: 4 + 1 = 5
Hundredths: 2 + 3 = 5
Tenths: 2 + 3 = 5
Ones: 7 + 6 = 13
→ 13.555
Correct.
---
⑩ 6.104 - 5.503
Thousandths: 4 - 3 = 1
Hundredths: 0 - 0 = 0
Tenths: 1 - 5 → borrow → 11 - 5 = 6
Ones: 6 becomes 5 → 5 - 5 = 0
→ 0.601
Check: 6.104 - 5.503 = 0.601 → correct.
---
⑪ 5.204 + 5.199
Thousandths: 4 + 9 = 13 → write 3, carry 1
Hundredths: 0 + 9 + 1 = 10 → write 0, carry 1
Tenths: 2 + 1 + 1 = 4
Ones: 5 + 5 = 10
→ 10.403
Check: 5.204 + 5.199 = 10.403 → correct.
---
⑫ 6.290 + 8.980
Thousandths: 0 + 0 = 0
Hundredths: 9 + 8 = 17 → write 7, carry 1
Tenths: 2 + 9 + 1 = 12 → write 2, carry 1
Ones: 6 + 8 + 1 = 15
→ 15.270
Correct.
---
⑬ 0.987 + 3.442
Thousandths: 7 + 2 = 9
Hundredths: 8 + 4 = 12 → write 2, carry 1
Tenths: 9 + 4 + 1 = 14 → write 4, carry 1
Ones: 0 + 3 + 1 = 4
→ 4.429
Correct.
---
⑭ 7.434 + 6.177
Thousandths: 4 + 7 = 11 → write 1, carry 1
Hundredths: 3 + 7 + 1 = 11 → write 1, carry 1
Tenths: 4 + 1 + 1 = 6
Ones: 7 + 6 = 13
→ 13.611
Correct.
---
⑮ 3.997 - 2.813
Thousandths: 7 - 3 = 4
Hundredths: 9 - 1 = 8
Tenths: 9 - 8 = 1
Ones: 3 - 2 = 1
→ 1.184
Correct.
---
⑯ 3.143 - 0.198
Thousandths: 3 - 8 → borrow → 13 - 8 = 5
Hundredths: 4 becomes 3 → 3 - 9 → borrow → 13 - 9 = 4
Tenths: 1 becomes 0 → 0 - 1 → borrow → 10 - 1 = 9 (ones digit reduces)
Ones: 3 becomes 2 → 2 - 0 = 2
→ 2.945
Check: 3.143 - 0.198 = ?
3.143 - 0.2 = 2.943, then add back 0.002 → 2.945 → correct.
---
Final Answer:
① 5.024
② 7.568
③ 0.770
④ 9.433
⑤ 1.784
⑥ 1.016
⑦ 12.654
⑧ 1.983
⑨ 13.555
⑩ 0.601
⑪ 10.403
⑫ 15.270
⑬ 4.429
⑭ 13.611
⑮ 1.184
⑯ 2.945
---
① 3.897 + 1.127
Add thousandths: 7 + 7 = 14 → write 4, carry 1
Hundredths: 9 + 2 + 1 = 12 → write 2, carry 1
Tenths: 8 + 1 + 1 = 10 → write 0, carry 1
Ones: 3 + 1 + 1 = 5
→ 5.024
---
② 9.387 - 1.819
Thousandths: 7 - 9 → can’t do, borrow → 17 - 9 = 8
Hundredths: 8 becomes 7 (after borrow) → 7 - 1 = 6
Tenths: 3 - 8 → can’t do, borrow → 13 - 8 = 5
Ones: 9 becomes 8 → 8 - 1 = 7
→ 7.568
Wait — let me double-check that subtraction:
Actually, better to align:
```
9.387
- 1.819
-------
```
Start from right:
7 - 9 → borrow → 17 - 9 = 8
8 becomes 7 → 7 - 1 = 6
3 becomes 2 (because we borrowed for tenths? Wait no — actually, when we borrowed for thousandths, hundredths digit was reduced by 1. Then for tenths: 3 - 8 → need to borrow from ones.
So:
Ones: 9 → becomes 8 after lending to tenths
Tenths: 3 becomes 13 → 13 - 8 = 5
Hundredths: 8 became 7 (from earlier borrow) → 7 - 1 = 6
Thousandths: 7 became 17 → 17 - 9 = 8
Yes → 7.568
But wait — 9.387 minus 1.819 should be less than 8? Let me calculate numerically:
9.387 - 1.819 = ?
Do 9.387 - 1 = 8.387
Then 8.387 - 0.8 = 7.587
Then 7.587 - 0.019 = 7.568 → yes, correct.
---
③ 1.944 - 1.174
Thousandths: 4 - 4 = 0
Hundredths: 4 - 7 → borrow → 14 - 7 = 7
Tenths: 9 becomes 8 → 8 - 1 = 7
Ones: 1 - 1 = 0
→ 0.770 → which is 0.77
But since it's to thousandths, keep as 0.770
Actually, 1.944 - 1.174:
= (1.944 - 1.000) = 0.944
Then 0.944 - 0.174 = 0.770 → yes.
---
④ 5.234 + 4.199
Thousandths: 4 + 9 = 13 → write 3, carry 1
Hundredths: 3 + 9 + 1 = 13 → write 3, carry 1
Tenths: 2 + 1 + 1 = 4
Ones: 5 + 4 = 9
→ 9.433
Check: 5.234 + 4.199 = 5.234 + 4 + 0.199 = 9.234 + 0.199 = 9.433 → correct.
---
⑤ 3.092 - 1.308
Thousandths: 2 - 8 → borrow → 12 - 8 = 4
Hundredths: 9 becomes 8 → 8 - 0 = 8
Tenths: 0 - 3 → borrow → 10 - 3 = 7 (but ones digit will reduce)
Ones: 3 becomes 2 → 2 - 1 = 1
→ 1.784
Check: 3.092 - 1.308 = ?
3.092 - 1 = 2.092
2.092 - 0.3 = 1.792
1.792 - 0.008 = 1.784 → correct.
---
⑥ 4.448 - 3.432
Thousandths: 8 - 2 = 6
Hundredths: 4 - 3 = 1
Tenths: 4 - 4 = 0
Ones: 4 - 3 = 1
→ 1.016
Easy check: 4.448 - 3.432 = 1.016 → correct.
---
⑦ 9.423 + 3.231
Thousandths: 3 + 1 = 4
Hundredths: 2 + 3 = 5
Tenths: 4 + 2 = 6
Ones: 9 + 3 = 12
→ 12.654
Correct.
---
⑧ 4.982 - 2.999
This is tricky. Think of it as 4.982 - 3 + 0.001 = 1.982 + 0.001 = 1.983
Or step by step:
Thousandths: 2 - 9 → borrow → 12 - 9 = 3
Hundredths: 8 becomes 7 → 7 - 9 → borrow → 17 - 9 = 8
Tenths: 9 becomes 8 → 8 - 9 → borrow → 18 - 9 = 9
Ones: 4 becomes 3 → 3 - 2 = 1
→ 1.983
Yes.
---
⑨ 7.224 + 6.331
Thousandths: 4 + 1 = 5
Hundredths: 2 + 3 = 5
Tenths: 2 + 3 = 5
Ones: 7 + 6 = 13
→ 13.555
Correct.
---
⑩ 6.104 - 5.503
Thousandths: 4 - 3 = 1
Hundredths: 0 - 0 = 0
Tenths: 1 - 5 → borrow → 11 - 5 = 6
Ones: 6 becomes 5 → 5 - 5 = 0
→ 0.601
Check: 6.104 - 5.503 = 0.601 → correct.
---
⑪ 5.204 + 5.199
Thousandths: 4 + 9 = 13 → write 3, carry 1
Hundredths: 0 + 9 + 1 = 10 → write 0, carry 1
Tenths: 2 + 1 + 1 = 4
Ones: 5 + 5 = 10
→ 10.403
Check: 5.204 + 5.199 = 10.403 → correct.
---
⑫ 6.290 + 8.980
Thousandths: 0 + 0 = 0
Hundredths: 9 + 8 = 17 → write 7, carry 1
Tenths: 2 + 9 + 1 = 12 → write 2, carry 1
Ones: 6 + 8 + 1 = 15
→ 15.270
Correct.
---
⑬ 0.987 + 3.442
Thousandths: 7 + 2 = 9
Hundredths: 8 + 4 = 12 → write 2, carry 1
Tenths: 9 + 4 + 1 = 14 → write 4, carry 1
Ones: 0 + 3 + 1 = 4
→ 4.429
Correct.
---
⑭ 7.434 + 6.177
Thousandths: 4 + 7 = 11 → write 1, carry 1
Hundredths: 3 + 7 + 1 = 11 → write 1, carry 1
Tenths: 4 + 1 + 1 = 6
Ones: 7 + 6 = 13
→ 13.611
Correct.
---
⑮ 3.997 - 2.813
Thousandths: 7 - 3 = 4
Hundredths: 9 - 1 = 8
Tenths: 9 - 8 = 1
Ones: 3 - 2 = 1
→ 1.184
Correct.
---
⑯ 3.143 - 0.198
Thousandths: 3 - 8 → borrow → 13 - 8 = 5
Hundredths: 4 becomes 3 → 3 - 9 → borrow → 13 - 9 = 4
Tenths: 1 becomes 0 → 0 - 1 → borrow → 10 - 1 = 9 (ones digit reduces)
Ones: 3 becomes 2 → 2 - 0 = 2
→ 2.945
Check: 3.143 - 0.198 = ?
3.143 - 0.2 = 2.943, then add back 0.002 → 2.945 → correct.
---
Final Answer:
① 5.024
② 7.568
③ 0.770
④ 9.433
⑤ 1.784
⑥ 1.016
⑦ 12.654
⑧ 1.983
⑨ 13.555
⑩ 0.601
⑪ 10.403
⑫ 15.270
⑬ 4.429
⑭ 13.611
⑮ 1.184
⑯ 2.945
Parent Tip: Review the logic above to help your child master the concept of adding decimals worksheet.
