Multiplying and Dividing Decimals Worksheets - Math Monks - Free Printable
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Step-by-step solution for: Multiplying and Dividing Decimals Worksheets - Math Monks
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Show Answer Key & Explanations
Step-by-step solution for: Multiplying and Dividing Decimals Worksheets - Math Monks
Let’s solve each problem step by step. We’ll start with the multiplication problems, then move to division.
---
Multiply Problems:
Problem 1: 27.31 × 6.3
Step 1: Ignore decimals and multiply as whole numbers:
2731 × 63
Break it down:
2731 × 60 = 163,860
2731 × 3 = 8,193
Add them: 163,860 + 8,193 = 172,053
Step 2: Count decimal places in original numbers:
27.31 → 2 decimal places
6.3 → 1 decimal place
Total = 3 decimal places
Step 3: Put decimal back in answer: 172.053
✔ Answer: 172.053
---
Problem 2: 1238.58 × 64.14
This is big — let’s do it carefully.
First, ignore decimals: 123858 × 6414
We can break 6414 into 6000 + 400 + 10 + 4
But that’s messy. Let’s use standard multiplication:
Actually, better to use calculator-style steps (since this is for a student, we’ll simulate careful hand math):
Alternatively, since this is time-consuming, let’s compute accurately:
1238.58 × 64.14
= (123858 / 100) × (6414 / 100) = (123858 × 6414) / 10000
Compute 123858 × 6414:
Let me compute step by step:
First, 123858 × 6000 = 743,148,000
123858 × 400 = 49,543,200
123858 × 10 = 1,238,580
123858 × 4 = 495,432
Now add:
743,148,000
+ 49,543,200 = 792,691,200
+ 1,238,580 = 793,929,780
+ 495,432 = 794,425,212
Now divide by 10,000 → move decimal 4 places left: 79,442.5212
Wait — check decimal places:
Original: 1238.58 has 2 decimals, 64.14 has 2 decimals → total 4 decimals → yes.
✔ Answer: 79442.5212
---
Problem 3: 63.24 × 12.20
Note: 12.20 is same as 12.2
Ignore decimals: 6324 × 1220
Or easier: 63.24 × 12.2
Compute 6324 × 122 = ?
6324 × 100 = 632,400
6324 × 20 = 126,480
6324 × 2 = 12,648
Add: 632,400 + 126,480 = 758,880 + 12,648 = 771,528
Now, since we multiplied 63.24 (2 decimals) × 12.2 (1 decimal) → total 3 decimals
So 771.528
But wait — original was 12.20, which is still 2 decimals? Actually, trailing zero doesn’t count — 12.20 is same as 12.2 → 1 decimal place? No!
Wait: 12.20 has two decimal places (even if last digit is zero). So:
63.24 → 2 decimals
12.20 → 2 decimals
Total = 4 decimals
So our product should have 4 decimal places.
We computed 6324 × 1220 = ?
Better: 63.24 × 12.20
Do 6324 × 1220 = ?
6324 × 1000 = 6,324,000
6324 × 200 = 1,264,800
6324 × 20 = 126,480
Wait — 1220 = 1000 + 200 + 20? No, 1220 = 1200 + 20
Easier: 6324 × 1220 = 6324 × (122 × 10) = (6324 × 122) × 10
We had 6324 × 122 = 771,528 → times 10 = 7,715,280
Now, since original numbers had 2 + 2 = 4 decimal places, divide by 10,000 → 771.5280
Which is 771.528
But to be precise: 7,715,280 ÷ 10,000 = 771.5280 → so 771.528
✔ Answer: 771.528
---
Problem 4: 73.45 × 83.11
Ignore decimals: 7345 × 8311
This is large — let’s compute:
7345 × 8000 = 58,760,000
7345 × 300 = 2,203,500
7345 × 10 = 73,450
7345 × 1 = 7,345
Add:
58,760,000
+ 2,203,500 = 60,963,500
+ 73,450 = 61,036,950
+ 7,345 = 61,044,295
Decimal places: 73.45 (2), 83.11 (2) → total 4
So 6104.4295
✔ Answer: 6104.4295
---
Problem 5: 1034.33 × 8.44
Ignore decimals: 103433 × 844
Compute:
103433 × 800 = 82,746,400
103433 × 40 = 4,137,320
103433 × 4 = 413,732
Add:
82,746,400
+ 4,137,320 = 86,883,720
+ 413,732 = 87,297,452
Decimal places: 1034.33 (2), 8.44 (2) → total 4
So 8729.7452
✔ Answer: 8729.7452
---
Problem 6: 0.313 × 0.224
Ignore decimals: 313 × 224
313 × 200 = 62,600
313 × 20 = 6,260
313 × 4 = 1,252
Add: 62,600 + 6,260 = 68,860 + 1,252 = 70,112
Decimal places: 0.313 (3), 0.224 (3) → total 6
So 0.070112
✔ Answer: 0.070112
---
Divide Problems:
Problem 1: 21.34 ÷ 10
Dividing by 10 moves decimal one place left: 2.134
✔ Answer: 2.134
---
Problem 2: 999.92 ÷ 100
Dividing by 100 moves decimal two places left: 9.9992
✔ Answer: 9.9992
---
Problem 3: 932.4 ÷ 121.32
This is trickier. Let’s make divisor whole number.
Multiply numerator and denominator by 100 to eliminate decimals:
932.4 × 100 = 93,240
121.32 × 100 = 12,132
Now compute 93240 ÷ 12132
Let’s divide:
12132 × 7 = 84,924
93,240 - 84,924 = 8,316
Bring down 0 → 83,160
12132 × 6 = 72,792
83,160 - 72,792 = 10,368
Bring down 0 → 103,680
12132 × 8 = 97,056
103,680 - 97,056 = 6,624
Bring down 0 → 66,240
12132 × 5 = 60,660
66,240 - 60,660 = 5,580
So approximately 7.685... but let’s see exact value.
Actually, better to use calculator or simplify.
Note: 932.4 ÷ 121.32
Let me compute directly:
121.32 × 7.68 = ?
121.32 × 7 = 849.24
121.32 × 0.6 = 72.792
121.32 × 0.08 = 9.7056
Sum: 849.24 + 72.792 = 922.032 + 9.7056 = 931.7376
Close to 932.4 → difference 0.6624
Now 121.32 × 0.005 = 0.6066 → close
So 7.685 → 121.32 × 7.685 = ?
Actually, let’s do proper division:
932.4 ÷ 121.32 = ?
Use long division or accept approximation.
But let’s compute exactly:
932.4 / 121.32 = 93240 / 12132 (multiply num and den by 100)
Simplify fraction:
Divide numerator and denominator by 12? Let’s find GCD.
Actually, 93240 ÷ 12132 ≈ 7.685
Check: 12132 × 7.685 = ?
12132 × 7 = 84924
12132 × 0.6 = 7279.2
12132 × 0.08 = 970.56
12132 × 0.005 = 60.66
Sum: 84924 + 7279.2 = 92203.2 + 970.56 = 93173.76 + 60.66 = 93234.42
But we have 93240 → difference 5.58
So 7.685 + (5.58/12132) ≈ 7.685 + 0.00046 ≈ 7.68546
But perhaps it's exact? Let me try 93240 ÷ 12132
Do division:
12132 ) 93240.000
12132 × 7 = 84924 → subtract from 93240 → 8316
Bring down 0 → 83160
12132 × 6 = 72792 → subtract → 10368
Bring down 0 → 103680
12132 × 8 = 97056 → subtract → 6624
Bring down 0 → 66240
12132 × 5 = 60660 → subtract → 5580
Bring down 0 → 55800
12132 × 4 = 48528 → subtract → 7272
And so on.
So quotient is 7.6854...
But for practical purposes, let’s say 7.685
Wait — maybe I made a mistake. Let me use another approach.
Note: 932.4 ÷ 121.32 = ?
Calculate numerically:
121.32 × 7.685 = as above ~932.34, very close to 932.4
Difference is small. Perhaps the problem expects rounding.
But let’s assume we need exact value.
Actually, 932.4 / 121.32 = 93240 / 12132 = reduce by dividing numerator and denominator by 12? Let’s see GCD.
Find GCD of 93240 and 12132.
Use Euclidean algorithm:
GCD(93240, 12132)
93240 ÷ 12132 = 7 times, remainder 93240 - 7*12132 = 93240 - 84924 = 8316
GCD(12132, 8316)
12132 ÷ 8316 = 1 time, remainder 12132 - 8316 = 3816
GCD(8316, 3816)
8316 ÷ 3816 = 2 times, remainder 8316 - 7632 = 684
GCD(3816, 684)
3816 ÷ 684 = 5 times, 5*684=3420, remainder 396
GCD(684, 396)
684 ÷ 396 = 1, remainder 288
GCD(396, 288)
396 ÷ 288 = 1, remainder 108
GCD(288, 108)
288 ÷ 108 = 2, remainder 72
GCD(108, 72) = 36
GCD(72, 36) = 36
So GCD is 36
Thus, 93240 ÷ 36 = 2590
12132 ÷ 36 = 337
So 2590 / 337
Now divide 2590 ÷ 337
337 × 7 = 2359
2590 - 2359 = 231
So 7 + 231/337 ≈ 7.68546
So approximately 7.685
But for worksheet, perhaps they expect rounded answer or exact fraction.
Since it's decimal worksheet, likely decimal answer.
Let’s take 7.685
But let’s verify with calculator simulation:
932.4 ÷ 121.32 = 7.68546... so to three decimals, 7.685
✔ Answer: 7.685 (rounded to three decimal places)
---
Problem 4: 9.4 ÷ 3.2
Make divisor whole: multiply num and den by 10 → 94 ÷ 32
94 ÷ 32 = 2.9375
Because 32 × 2 = 64, 94-64=30, bring down 0 → 300, 32×9=288, remainder 12, bring down 0 → 120, 32×3=96, remainder 24, bring down 0 → 240, 32×7=224, remainder 16, bring down 0 → 160, 32×5=160, done.
So 2.9375
✔ Answer: 2.9375
---
Problem 5: 98.6 ÷ 18.4
Multiply num and den by 10: 986 ÷ 184
184 × 5 = 920
986 - 920 = 66
Bring down 0 → 660
184 × 3 = 552
660 - 552 = 108
Bring down 0 → 1080
184 × 5 = 920
1080 - 920 = 160
Bring down 0 → 1600
184 × 8 = 1472
1600 - 1472 = 128
Bring down 0 → 1280
184 × 6 = 1104
1280 - 1104 = 176
etc.
So 5.3586...
Approximately 5.359
But let’s compute exactly:
986 ÷ 184 = 493 ÷ 92 (divide by 2)
493 ÷ 92
92 × 5 = 460
493 - 460 = 33
So 5 + 33/92 = 5.358695...
To three decimals: 5.359
✔ Answer: 5.359 (rounded)
---
Problem 6: 256.58 ÷ 16
Divide directly.
16 into 256.58
16 × 16 = 256 → so 16.000
Remainder 0.58
0.58 ÷ 16 = 0.03625
So total 16.03625
Check: 16 × 16.03625 = 16×16 = 256, 16×0.03625=0.58, yes.
✔ Answer: 16.03625
---
Now, compiling all answers:
Multiplication:
1. 172.053
2. 79442.5212
3. 771.528
4. 6104.4295
5. 8729.7452
6. 0.070112
Division:
1. 2.134
2. 9.9992
3. 7.685 (approx)
4. 2.9375
5. 5.359 (approx)
6. 16.03625
For division problem 3 and 5, since they are repeating or long decimals, we'll round to three decimal places as typical for such worksheets.
Final Answers:
Final Answer:
Multiply:
1. 172.053
2. 79442.5212
3. 771.528
4. 6104.4295
5. 8729.7452
6. 0.070112
Divide:
1. 2.134
2. 9.9992
3. 7.685
4. 2.9375
5. 5.359
6. 16.03625
---
Multiply Problems:
Problem 1: 27.31 × 6.3
Step 1: Ignore decimals and multiply as whole numbers:
2731 × 63
Break it down:
2731 × 60 = 163,860
2731 × 3 = 8,193
Add them: 163,860 + 8,193 = 172,053
Step 2: Count decimal places in original numbers:
27.31 → 2 decimal places
6.3 → 1 decimal place
Total = 3 decimal places
Step 3: Put decimal back in answer: 172.053
✔ Answer: 172.053
---
Problem 2: 1238.58 × 64.14
This is big — let’s do it carefully.
First, ignore decimals: 123858 × 6414
We can break 6414 into 6000 + 400 + 10 + 4
But that’s messy. Let’s use standard multiplication:
Actually, better to use calculator-style steps (since this is for a student, we’ll simulate careful hand math):
Alternatively, since this is time-consuming, let’s compute accurately:
1238.58 × 64.14
= (123858 / 100) × (6414 / 100) = (123858 × 6414) / 10000
Compute 123858 × 6414:
Let me compute step by step:
First, 123858 × 6000 = 743,148,000
123858 × 400 = 49,543,200
123858 × 10 = 1,238,580
123858 × 4 = 495,432
Now add:
743,148,000
+ 49,543,200 = 792,691,200
+ 1,238,580 = 793,929,780
+ 495,432 = 794,425,212
Now divide by 10,000 → move decimal 4 places left: 79,442.5212
Wait — check decimal places:
Original: 1238.58 has 2 decimals, 64.14 has 2 decimals → total 4 decimals → yes.
✔ Answer: 79442.5212
---
Problem 3: 63.24 × 12.20
Note: 12.20 is same as 12.2
Ignore decimals: 6324 × 1220
Or easier: 63.24 × 12.2
Compute 6324 × 122 = ?
6324 × 100 = 632,400
6324 × 20 = 126,480
6324 × 2 = 12,648
Add: 632,400 + 126,480 = 758,880 + 12,648 = 771,528
Now, since we multiplied 63.24 (2 decimals) × 12.2 (1 decimal) → total 3 decimals
So 771.528
But wait — original was 12.20, which is still 2 decimals? Actually, trailing zero doesn’t count — 12.20 is same as 12.2 → 1 decimal place? No!
Wait: 12.20 has two decimal places (even if last digit is zero). So:
63.24 → 2 decimals
12.20 → 2 decimals
Total = 4 decimals
So our product should have 4 decimal places.
We computed 6324 × 1220 = ?
Better: 63.24 × 12.20
Do 6324 × 1220 = ?
6324 × 1000 = 6,324,000
6324 × 200 = 1,264,800
6324 × 20 = 126,480
Wait — 1220 = 1000 + 200 + 20? No, 1220 = 1200 + 20
Easier: 6324 × 1220 = 6324 × (122 × 10) = (6324 × 122) × 10
We had 6324 × 122 = 771,528 → times 10 = 7,715,280
Now, since original numbers had 2 + 2 = 4 decimal places, divide by 10,000 → 771.5280
Which is 771.528
But to be precise: 7,715,280 ÷ 10,000 = 771.5280 → so 771.528
✔ Answer: 771.528
---
Problem 4: 73.45 × 83.11
Ignore decimals: 7345 × 8311
This is large — let’s compute:
7345 × 8000 = 58,760,000
7345 × 300 = 2,203,500
7345 × 10 = 73,450
7345 × 1 = 7,345
Add:
58,760,000
+ 2,203,500 = 60,963,500
+ 73,450 = 61,036,950
+ 7,345 = 61,044,295
Decimal places: 73.45 (2), 83.11 (2) → total 4
So 6104.4295
✔ Answer: 6104.4295
---
Problem 5: 1034.33 × 8.44
Ignore decimals: 103433 × 844
Compute:
103433 × 800 = 82,746,400
103433 × 40 = 4,137,320
103433 × 4 = 413,732
Add:
82,746,400
+ 4,137,320 = 86,883,720
+ 413,732 = 87,297,452
Decimal places: 1034.33 (2), 8.44 (2) → total 4
So 8729.7452
✔ Answer: 8729.7452
---
Problem 6: 0.313 × 0.224
Ignore decimals: 313 × 224
313 × 200 = 62,600
313 × 20 = 6,260
313 × 4 = 1,252
Add: 62,600 + 6,260 = 68,860 + 1,252 = 70,112
Decimal places: 0.313 (3), 0.224 (3) → total 6
So 0.070112
✔ Answer: 0.070112
---
Divide Problems:
Problem 1: 21.34 ÷ 10
Dividing by 10 moves decimal one place left: 2.134
✔ Answer: 2.134
---
Problem 2: 999.92 ÷ 100
Dividing by 100 moves decimal two places left: 9.9992
✔ Answer: 9.9992
---
Problem 3: 932.4 ÷ 121.32
This is trickier. Let’s make divisor whole number.
Multiply numerator and denominator by 100 to eliminate decimals:
932.4 × 100 = 93,240
121.32 × 100 = 12,132
Now compute 93240 ÷ 12132
Let’s divide:
12132 × 7 = 84,924
93,240 - 84,924 = 8,316
Bring down 0 → 83,160
12132 × 6 = 72,792
83,160 - 72,792 = 10,368
Bring down 0 → 103,680
12132 × 8 = 97,056
103,680 - 97,056 = 6,624
Bring down 0 → 66,240
12132 × 5 = 60,660
66,240 - 60,660 = 5,580
So approximately 7.685... but let’s see exact value.
Actually, better to use calculator or simplify.
Note: 932.4 ÷ 121.32
Let me compute directly:
121.32 × 7.68 = ?
121.32 × 7 = 849.24
121.32 × 0.6 = 72.792
121.32 × 0.08 = 9.7056
Sum: 849.24 + 72.792 = 922.032 + 9.7056 = 931.7376
Close to 932.4 → difference 0.6624
Now 121.32 × 0.005 = 0.6066 → close
So 7.685 → 121.32 × 7.685 = ?
Actually, let’s do proper division:
932.4 ÷ 121.32 = ?
Use long division or accept approximation.
But let’s compute exactly:
932.4 / 121.32 = 93240 / 12132 (multiply num and den by 100)
Simplify fraction:
Divide numerator and denominator by 12? Let’s find GCD.
Actually, 93240 ÷ 12132 ≈ 7.685
Check: 12132 × 7.685 = ?
12132 × 7 = 84924
12132 × 0.6 = 7279.2
12132 × 0.08 = 970.56
12132 × 0.005 = 60.66
Sum: 84924 + 7279.2 = 92203.2 + 970.56 = 93173.76 + 60.66 = 93234.42
But we have 93240 → difference 5.58
So 7.685 + (5.58/12132) ≈ 7.685 + 0.00046 ≈ 7.68546
But perhaps it's exact? Let me try 93240 ÷ 12132
Do division:
12132 ) 93240.000
12132 × 7 = 84924 → subtract from 93240 → 8316
Bring down 0 → 83160
12132 × 6 = 72792 → subtract → 10368
Bring down 0 → 103680
12132 × 8 = 97056 → subtract → 6624
Bring down 0 → 66240
12132 × 5 = 60660 → subtract → 5580
Bring down 0 → 55800
12132 × 4 = 48528 → subtract → 7272
And so on.
So quotient is 7.6854...
But for practical purposes, let’s say 7.685
Wait — maybe I made a mistake. Let me use another approach.
Note: 932.4 ÷ 121.32 = ?
Calculate numerically:
121.32 × 7.685 = as above ~932.34, very close to 932.4
Difference is small. Perhaps the problem expects rounding.
But let’s assume we need exact value.
Actually, 932.4 / 121.32 = 93240 / 12132 = reduce by dividing numerator and denominator by 12? Let’s see GCD.
Find GCD of 93240 and 12132.
Use Euclidean algorithm:
GCD(93240, 12132)
93240 ÷ 12132 = 7 times, remainder 93240 - 7*12132 = 93240 - 84924 = 8316
GCD(12132, 8316)
12132 ÷ 8316 = 1 time, remainder 12132 - 8316 = 3816
GCD(8316, 3816)
8316 ÷ 3816 = 2 times, remainder 8316 - 7632 = 684
GCD(3816, 684)
3816 ÷ 684 = 5 times, 5*684=3420, remainder 396
GCD(684, 396)
684 ÷ 396 = 1, remainder 288
GCD(396, 288)
396 ÷ 288 = 1, remainder 108
GCD(288, 108)
288 ÷ 108 = 2, remainder 72
GCD(108, 72) = 36
GCD(72, 36) = 36
So GCD is 36
Thus, 93240 ÷ 36 = 2590
12132 ÷ 36 = 337
So 2590 / 337
Now divide 2590 ÷ 337
337 × 7 = 2359
2590 - 2359 = 231
So 7 + 231/337 ≈ 7.68546
So approximately 7.685
But for worksheet, perhaps they expect rounded answer or exact fraction.
Since it's decimal worksheet, likely decimal answer.
Let’s take 7.685
But let’s verify with calculator simulation:
932.4 ÷ 121.32 = 7.68546... so to three decimals, 7.685
✔ Answer: 7.685 (rounded to three decimal places)
---
Problem 4: 9.4 ÷ 3.2
Make divisor whole: multiply num and den by 10 → 94 ÷ 32
94 ÷ 32 = 2.9375
Because 32 × 2 = 64, 94-64=30, bring down 0 → 300, 32×9=288, remainder 12, bring down 0 → 120, 32×3=96, remainder 24, bring down 0 → 240, 32×7=224, remainder 16, bring down 0 → 160, 32×5=160, done.
So 2.9375
✔ Answer: 2.9375
---
Problem 5: 98.6 ÷ 18.4
Multiply num and den by 10: 986 ÷ 184
184 × 5 = 920
986 - 920 = 66
Bring down 0 → 660
184 × 3 = 552
660 - 552 = 108
Bring down 0 → 1080
184 × 5 = 920
1080 - 920 = 160
Bring down 0 → 1600
184 × 8 = 1472
1600 - 1472 = 128
Bring down 0 → 1280
184 × 6 = 1104
1280 - 1104 = 176
etc.
So 5.3586...
Approximately 5.359
But let’s compute exactly:
986 ÷ 184 = 493 ÷ 92 (divide by 2)
493 ÷ 92
92 × 5 = 460
493 - 460 = 33
So 5 + 33/92 = 5.358695...
To three decimals: 5.359
✔ Answer: 5.359 (rounded)
---
Problem 6: 256.58 ÷ 16
Divide directly.
16 into 256.58
16 × 16 = 256 → so 16.000
Remainder 0.58
0.58 ÷ 16 = 0.03625
So total 16.03625
Check: 16 × 16.03625 = 16×16 = 256, 16×0.03625=0.58, yes.
✔ Answer: 16.03625
---
Now, compiling all answers:
Multiplication:
1. 172.053
2. 79442.5212
3. 771.528
4. 6104.4295
5. 8729.7452
6. 0.070112
Division:
1. 2.134
2. 9.9992
3. 7.685 (approx)
4. 2.9375
5. 5.359 (approx)
6. 16.03625
For division problem 3 and 5, since they are repeating or long decimals, we'll round to three decimal places as typical for such worksheets.
Final Answers:
Final Answer:
Multiply:
1. 172.053
2. 79442.5212
3. 771.528
4. 6104.4295
5. 8729.7452
6. 0.070112
Divide:
1. 2.134
2. 9.9992
3. 7.685
4. 2.9375
5. 5.359
6. 16.03625
Parent Tip: Review the logic above to help your child master the concept of decimal mixed operations worksheet.