- Fractions, Decimals and Cancelling down

Question 1

What is cancelling down?

Answer 1

Cancelling down is reducing a fraction to its smallest possible version

eg 10 [divided by 10] 1

__ = __

20 [divided by 10] 2

Question 2

When do you use Equivalent fractions

Answer 2

Equivalent fractions are useful when you need to

compare a different range of fractions

eg

3 ,1 , 7

__ __ __

5 4 10

because 4, 5 and 10 all divide into 20 you can change them to out of 20

12 5 14

__ __ __

20 20 20

Question 3

Adding and subtracting fractions

Answer 3

Adding and subtracting fractions:

fractions with different denominators need to be rewritten as equivalent fractions

eg

2 1

__ + __

7 4

7 and 4 both go into 28 [x 4] [x 7]

8 7

__ + __

28 28

or

2 x 4 1 x 7

_____ x ____

7 x 4 4 x 7

Question 4

How do you multiply and divide fractions?

Answer 4

Multiply is straight forward:

times the top and then times the bottom

4 2 8

__ x __ = __

7 5 35

Divide:

4 2

__ ÷ __

7 5

*like magic if you REVERSE the second fraction

and change to x it works:

4 5 20

__ x __ = __

7 2 14

Question 5

Multiplying and dividing fractions by whole numbers

Answer 5

To Multiply and divide fractions by whole numbers

write the whole numeras as

N

__

1

eg

3

___ x 4

7

rewrite as

3 4

__ x __

7 1

remember to cancel down if possible

eg

5

__ x 4

24

rewrite as

5 4

__ x __

24 1

[24 and 4 can be divided by 4 so 24 becomes 6 and 4 becomes 1]

= 5 1

__ x __

6 1