Multiply and divide fractions and mixed numbers, reciprocals, and fraction problems like recipes and cutting lengths.
What you will learn
- Multiply fractions
- Divide by a fraction using the reciprocal
- Multiply and divide mixed numbers
- Scale recipes and share lengths
Multiplying
Multiply the tops and multiply the bottoms, then simplify: 2/3 × 3/5 = 6/15 = 2/5.
You can cancel first to keep the numbers small.
Mixed numbers must become improper fractions first: 2 1/3 × 1 1/2 = 7/3 × 3/2 = 21/6 = 3 1/2. Multiplying the whole numbers and the fractions separately (2 × 1 and 1/3 × 1/2) misses part of the answer.
The rest of this lesson and its 7 practice questions are locked.
In this lesson
- Multiplying
- Dividing
- Try it: Divide on the calculator
7 practice questions, marked as you go; about 20 minutes in all.
Key terms
Reciprocal
In this unit: Fractions, decimals and percentages
Calculate with fractions and mixed numbers, move between fractions, decimals and percentages, and solve percentage problems, including reverse percentages.
- Working with fractions
- Multiplying and dividing fractions
- Fractions, decimals and percentages
- Percentages
- Reverse percentages and repeated change