1. Multiplying with Fractions
Mathematics
Multiplying with Fractions

2. Lesson Objectives The aim of this powerpoint is to help you…
to multiply fractions by whole numbers
to multiply fractions by fractions

3. Multiplying Fractions
FIRSTLY convert any mixed numbers into improper fractions or write whole numbers over 1, then…
Multiply the top numbers together
Multiply the bottom numbers together
Cancel down (if possible) and/or convert your improper fraction back into a mixed number

4. 5 1 Example 1 3 10 If you need to simplify your answer… 15 3 1 10 2 2
What are 5 lots of 3/10? 3 10
If you need to simplify your answer…
5 3
1 10
5×3 15
1×10 10 5 × = × = = ÷5   1

5. Example 2 What is the product of 3/5 and 2/9? 3 2 5 9
3 2
5 9
If you need to simplify your answer…
6 2
45 15
3×2 6
5×9 45 × = = ÷3 

6. Of… The word ‘of’ in mathematics implies ‘multiply’
Therefore 3/5 of 2/9 means 3/5 × 2/9 (we did this in example 2)
We can represent this pictorially…
Draw a rectangle.
Split it into 9 columns and shade 2 of them in yellow (this is the 2/9)
Split it into 5 rows and shade 3 of them in blue (this is the 3/5)
The overlapping ‘green’ section is 3/5 of 2/9 = 6/45 or 2/15

7. Example 2 (pictorially)9 3 5 3× 5× of = = =

8. Quick Practice
A D 7 4
B E 8 3
C F 2 15
Work out your answers before clicking on to the next slide. × × × × × ×

9. Answers
D × =
E × =
F × =
A × =
B × =
C × =
6 35 or
3 32
or 2 5 or or

10. What next?
Print out the notes called Frac5. Read them and make sure you answer any questions
Work through all of the MyMaths lesson called Multiplying Fractions found at:
If you need more practice, try the worksheet called
MFrac-S0.xlsx.
Now move on to the Frac-6 powerpoint