Multiplying and Dividing Fractions - Complete Interactive Lesson
Part 1: ✖️ Multiplying Fractions
✖️ Multiplying Fractions
Good news: multiplying fractions is one of the easiest things you can do with fractions. You do not need a common denominator like you do for adding or subtracting. You just go straight across.
The Rule
To multiply two fractions:
- Multiply the numerators (the top numbers)
- Multiply the denominators (the bottom numbers)
- Simplify the answer if you can
Written as a formula:
The tops go across, and the bottoms go across. That's the whole trick!
A First Example
Let's multiply .
A Smart Shortcut: Cancel First ✂️
Sometimes you can cancel a common factor before you multiply. This keeps the numbers small.
Look at . The number is on top in one fraction and on the bottom in the other, so we can cancel both 3s:
Concept Check 🎯
Part 2: 📝 Worked Examples: Multiplying
📝 Worked Examples: Multiplying
Example 1 — Multiply, then simplify
Part 3: Dividing Fractions: Keep, Change, Flip
➗ Dividing Fractions: Keep, Change, Flip
Dividing fractions uses a trick called Keep–Change–Flip (KCF):
- Keep the first fraction the same.
- Change the sign into a sign.
- Flip the second fraction upside down (its reciprocal).
Then just multiply!
Reciprocal means you swap the top and bottom:
| Fraction | Reciprocal |
|---|---|
Part 4: 🌍 Fractions in Real Life
🌍 Fractions in Real Life
Fractions show up all the time in cooking, building, and sharing. Remember the two clues:
- "of" usually means multiply. Half of a recipe → multiply by .
- "split into equal parts" usually means divide. Sharing a board into equal pieces → divide.
Recipe example: A recipe uses cup of sugar, but you only want to make the recipe.
Part 5: Review & Challenge
🏆 Review & Challenge
You now know how to multiply and divide fractions. Here is the whole idea on one card:
| Operation | What to do | Example |
|---|---|---|
| Multiply | Tops across, bottoms across, then simplify |