Dividing Decimals
Learn how to divide decimal numbers step by step.
For Elementary Students
Dividing a Decimal by a Whole Number
This is the easiest type! Just divide like normal and put the decimal point in the answer right above where it is in the problem.
Think about it like this: The decimal point goes straight up — like an elevator!
Example: 8.4 ÷ 4 = ?
Step 1: Set up like regular division
---
4 | 8.4
Step 2: Divide 8 by 4 = 2
2
---
4 | 8.4
8
Step 3: Put the decimal point in the answer (right above the one in 8.4!)
2.
----
4 | 8.4
8
0
Step 4: Bring down the 4 and divide
- 4 ÷ 4 = 1
2.1
----
4 | 8.4
− 8 ↓
04
− 4
0
Answer: 8.4 ÷ 4 = 2.1
Another Example: 15.6 ÷ 3
5.2
----
3 | 15.6
− 15 ↓
06
− 6
0
- 3 into 15 = 5
- Put decimal point straight up
- 3 into 6 = 2
Answer: 5.2
Dividing by a Decimal: Make It a Whole Number!
When you're dividing by a decimal, you need to make it a whole number first!
The trick: Move the decimal point to the right until the divisor is a whole number. Then move the decimal in the dividend the same number of places!
Example: 7.2 ÷ 0.3 = ?
Step 1: The divisor is 0.3 (a decimal). Move the decimal 1 place right → 3
Step 2: Move the decimal in 7.2 the same amount (1 place right) → 72
Step 3: Now divide: 72 ÷ 3 = 24
Answer: 24
Memory trick: Whatever you do to one side, do to the other!
Quick Trick: Dividing by 10, 100, 1000
Super easy shortcut!
Divide by 10: Move the decimal point 1 place left
45.3 ÷ 10 = 4.53
Divide by 100: Move it 2 places left
45.3 ÷ 100 = 0.453
Divide by 1000: Move it 3 places left
45.3 ÷ 1000 = 0.0453
Memory trick: Dividing makes numbers smaller, so the decimal moves LEFT!
For Junior High Students
Dividing a Decimal by a Whole Number
This works just like long division. Place the decimal point in the answer directly above where it is in the dividend.
Key rule: The decimal point in the quotient (answer) goes directly above the decimal point in the dividend.
Example: 8.4 ÷ 4
2.1
----
4 | 8.4
− 8 ↓
04
− 4
0
Steps:
- Divide:
4into8= 2 - Place the decimal point in the answer above the dividend's decimal
- Bring down:
4into4= 1
Answer: 2.1
Example: 15.6 ÷ 3
5.2
----
3 | 15.6
− 15 ↓
06
− 6
0
3into15= 5- Decimal point goes up
3into6= 2
Answer: 5.2
Dividing by a Decimal
When the divisor is a decimal, you need to make it a whole number first.
The Method:
- Move the decimal point in the divisor to the right until it's a whole number
- Move the decimal point in the dividend the same number of places to the right
- Now divide as normal
Why it works: This is equivalent to multiplying both numbers by the same power of 10, which doesn't change the quotient.
Example: 7.2 ÷ 0.3
Step 1: Move the decimal in 0.3 one place right → 3
Step 2: Move the decimal in 7.2 one place right → 72
Step 3: Divide: 72 ÷ 3 = 24
24
----
3 | 72
− 6 ↓
12
− 12
0
Answer: 24
Verification: 24 × 0.3 = 7.2 ✓
Example: 4.86 ÷ 0.02
Step 1: Move decimals two places right: 486 ÷ 2
Step 2: Divide
243
-----
2 | 486
− 4 ↓
08
− 8
06
− 6
0
Answer: 243
Visual Guide for Moving Decimals
Original: 7.2 ÷ 0.3
Move both decimals 1 place right:
7.2 → 72
0.3 → 3
Original: 4.86 ÷ 0.02
Move both decimals 2 places right:
4.86 → 486
0.02 → 2
Dividing by 10, 100, 1000
These are shortcuts — move the decimal point left:
Divide by 10: Move 1 place left
45.3 ÷ 10 = 4.53
Divide by 100: Move 2 places left
45.3 ÷ 100 = 0.453
Divide by 1000: Move 3 places left
45.3 ÷ 1000 = 0.0453
Why it works: Dividing by 10 is the inverse of multiplying by 10. Each division by 10 decreases the place value of each digit by one position.
Pattern:
- Multiply by 10 → decimal moves right
- Divide by 10 → decimal moves left
When Division Doesn't Come Out Even
Sometimes you'll get a remainder. Add zeros after the decimal point in the dividend and keep dividing.
Example: 5 ÷ 4
1.25
------
4 | 5.00
− 4 ↓
10
− 8
20
− 20
0
Steps:
4into5= 1 remainder 1- Add decimal point and zero:
1.0→ bring down to get10 4into10= 2 remainder 2- Add another zero, bring down to get
20 4into20= 5
Answer: 1.25
Example: 7 ÷ 8
0.875
------
8 | 7.000
− 0 ↓
70
− 64
60
− 56
40
− 40
0
Answer: 0.875
Repeating Decimals
Some divisions never end — they repeat forever!
Example: 1 ÷ 3 = 0.333333...
We write this as 0.3̄ (the bar means the 3 repeats)
Example: 2 ÷ 11 = 0.181818...
Written as 0.1̄8̄ (both digits repeat)
In practice: Round to a certain number of decimal places.
1 ÷ 3 ≈ 0.33(rounded to 2 decimal places)
Estimating to Check Answers
Always estimate first.
Example: 7.2 ÷ 0.3
Estimate: Think 7 ÷ 0.3
- Since
0.3 × 20 = 6and0.3 × 24 = 7.2 - Answer should be around 20-24
Actual: 24 ✓ Makes sense!
Example: 4.86 ÷ 0.02
Estimate: 5 ÷ 0.02
0.02 × 100 = 2, so0.02 × 250 = 5- Answer should be around 250
Actual: 243 ✓ Close!
Real-Life Applications
Sharing: "Divide $8.40 equally among 4 people"
$8.40 ÷ 4 = $2.10 per person
Unit price: "1.5 pounds costs $6.75. Price per pound?"
$6.75 ÷ 1.5
= $67.5 ÷ 15 (move decimals 1 place)
= $4.50 per pound
Conversion: "Run 10.5 km in 1.5 hours. Speed in km/hour?"
10.5 ÷ 1.5
= 105 ÷ 15 (move decimals 1 place)
= 7 km/hour
Common Mistakes
Mistake 1: Forgetting to move the decimal in the dividend
❌ 7.2 ÷ 0.3 → only changing divisor to 3 but keeping 7.2
✓ Move both: 72 ÷ 3
Mistake 2: Not placing decimal point in quotient correctly
❌ Forgetting to put decimal point straight up ✓ Always align the decimal point vertically
Mistake 3: Moving decimals the wrong number of places
❌ 4.86 ÷ 0.02 → moving 1 place instead of 2
✓ Count decimal places in divisor: 0.02 has 2 places, move 2
Tips for Success
Tip 1: When dividing by a decimal, move both decimals the same number of places
Tip 2: The decimal point in the answer goes straight up from the dividend
Tip 3: For dividing by 10, 100, 1000 — just move the decimal left (no long division needed!)
Tip 4: Always estimate to check if your answer makes sense
Tip 5: Add zeros after the decimal if division doesn't come out even
Practice
What is 9.6 ÷ 4?
What is 6.5 ÷ 0.5?
What is 240 ÷ 100?
What is 8.4 ÷ 0.2?