Dividing Decimals - Complete Interactive Lesson
Part 1: Why Do We Divide Decimals? 🍕
Why Do We Divide Decimals? 🍕
Division means splitting something into equal groups or sharing it fairly. We do this with decimals all the time in real life:
- Splitting a bill: $45.75 ÷ 3 friends
- Finding the unit price: $6.75 for snacks → how much is one?
- Sharing a measurement: feet of rope pieces
A decimal is just a number with a point in it, like or . Dividing decimals uses the same long division you already know — we just have to take good care of that little decimal point.
Dividing a Decimal by a Whole Number ➗
The easiest case is when the number you are dividing by (the divisor) is a whole number.
Example:
The big trick: bring the decimal point straight up into your answer, then divide like normal!
4.2
------
3 | 12.6
12
--
06
6
--
0 ✓
Step by step:
- The decimal point in is between the and the . Bring it to that same spot in the answer.
⭐ The Key Rule for Dividing BY a Decimal
What if you divide by a decimal, like ? We don't like dividing by a decimal, so we change it!
Make the divisor (the outside number) a whole number by moving its decimal point to the right.
Then move the decimal point the SAME number of places in the dividend (the inside number).
| Original problem | Move decimals | New problem |
|---|---|---|
| 1 place right |
Quick Concept Check ✅
Let's make sure the big idea is clear.
Part 2: Worked Example: Dividing by a Decimal
Worked Example: Dividing by a Decimal 🧮
Let's fully solve , one step at a time.
Step 1 — Make the divisor a whole number. Move the decimal in one place right → it becomes .
Step 2 — Move the dividend the SAME number of places. Move the decimal in one place right → it becomes .
Part 3: Multiple Choice
Multiple Choice 🎯
Work through each one carefully. Move the decimals first if you are dividing by a decimal!
Dividing by 10, 100, and 1,000 🔽
Quick rule: dividing by , , or just moves the decimal point to the LEFT!
- → move 1 place left
- → move places left
Part 4: Dividing Decimals in the Real World 🌎
Dividing Decimals in the Real World 🌎
Dividing decimals helps us share money fairly and find the price of one item.
Splitting a bill: Three friends split a $47.85 dinner evenly. How much does each pay?
Solve $47.85 ÷ 3:
15.95
-------
3 | 47.85
3
--
17
15
--
28
27
--
15
15
--
0 ✓
Each friend pays $15.95.
Finding the unit price: apples cost $3.96. How much is one apple?
Solve $3.96 ÷ 4 = $0.99 per apple. Knowing the unit price lets you compare deals at the store. Now try a few yourself!
Word Problem Practice 💵
Type each answer as a decimal number (no dollar sign needed), like 0.99.
- A -foot rope is cut into equal pieces. How long is each piece (in feet)?
Part 5: Review: Everything You Learned
Review: Everything You Learned 📋
You can now divide decimals like a pro! Here is a quick summary.
| Situation | What to do | Example |
|---|---|---|
| Decimal whole number | Bring the point straight up, then divide | |
| Dividing by a decimal | Move BOTH decimals right to make the divisor whole |