#### Transcript of Fractions, Decimals and Percentages

Some common conversions you need to know without having to work them out:

Cancelling Down

Divide the top and the bottom by the same number

You also need

to know how to

convert between all 3

Fraction

Decimal

Percentage

**Fractions, Decimals and Percentages**

**Fractions, Decimals and Percentages**

These are simply 3 ways of expressing a

proportion

of something.

They are

completely interchangeable

.

If someone tells you that they want

half

of your cake it's the same as saying they want

0.5

of it or

50%

.

Calculating with Fractions

There are a few simple rules for carrying out calculations with fractions.

A couple of things to note:

A number with a dot above it means the number repeats forever.

These are known as

recurring

decimals.

...and

Divide

Times by 100

Divide by 100

Er...this is a little more tricky

Converting

Decimals to Fractions

For decimals with 1 decimal place

0.6

0.3

0.8

0.X

take the digit in the first decimal place and put it over 10

In the same way we can

convert decimals with 2 or 3 decimal places

0.12

0.48

0.05

0.007

0.908

0.064

0.XY

0.XYZ

by putting them over 100 or 1000

What about those pesky recurring decimals?

1st

Find the

length

of the repeating sequence and

multiply

to move it past the decimal point

e.g 0.

216

216216... x 1000 =

216

.216216...

2nd

Subtract

the original number, r, from the new one

e.g

1000r

- r =

216.216216...

- 0.216216... = 216

so we have

999r = 216

3rd

All you need to do is

divide

to leave r...

e.g r

...and cancel if you can

e.g r

You could just learn the result:

Effectively, the fraction will always have the

repeating unit

on top and the

same number of 9s

on the bottom.

Don't forget to cancel down if you can.

Keep going until you can't find a number that will divide BOTH top and bottom.

Ordering Fractions

Start by putting each fraction over the same denominator.

So in order we have:

or, in other words:

Always change mixed numbers into improper fractions BEFORE you carry out any calculations.

=

Multiplying Fractions

Simply multiply the top and bottom of the fractions separately

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