revision guide ratio - flow mathematics · equivalent ratios and simplifying click for more...

RatioRevision Guide

By Flow Mathematics

flowmathematics.co.uk

F o u n d a t i o n

a n d h i g h e rFor Edexcel,

AQA and OCR

Get examready

Contents

Ratios and fractions

Simplifying ratios

Sharing in a ratio

Map scale

Converting units of area

Converting units of volume

Combining ratios

Probabilities and ratios

Questions

1

For bestresults...

Make Chrome, Safari or Firefox yourdefault browser.

1.

2. Login to the Flow Mathematics app.

Links will then take you straight to theanswers and where to find more examples.

Go to the apphere

2

Grade2/3

Answer

Answer

3

Ratios and fractions

Click formore examples

Girls to boys means we put the 1 girl first.

Example 1

Example 2

Boys to girls means we put the 3 boys first.

Example 3

This means:3 milk chocolates1 dark chocolate

5 white chocolates

TipAdd the numbers

to get the denominator.

Grade2/3

4

Equivalent ratios and simplifying

Click formore examples

Example: Ratios Example: Fractions

AnswerAnswer

Divide both partsby common factors

Quick method

Divide both partsby the highest

common factor.

Quick method

Example: Three numbers

7 is the highestcommon factor

of 35, 21 and 49.

Answer

Grade3

Answer

Click formore examples 5

Sharing in a ratio

Example 1 Example 2

Tina gets 3 potsand Ria gets 4.

The £21 is sharedequally between

the 7 pots.

Example 3

Answer

AnswerHere are the pots

in the ratio 7:2.Callum has 5 more.

The 5 pots containa total of £30.Divide by 5 to find how muchis in each pot.

Multiply £3by the numbers

in the ratio.

Grade3

Example 2

Answer

Click formore examples

Map scale

6

Example 1

Answer Answer

Key idea

This means 1cmon the map represents20,000cm in real life.

Divide 20,000 by 100to change to metres.

Grade3/4

Click formore examples

Converting units of area

7

Area = 100 x 100 Area = 10,000cm

2

Area = 1000 x 1000 Area = 1,000,000m

2

Area = 10 x 10 Area = 100mm

2

Square metres to square centimetres

Square kilometres to square metres

Square centimetres to square millimetres

Why?

Why?

Why?Change the lengths of a square metre

to centimetres.

Then calculatethe new area!

Change the lengths of a

square kilometre to metres.

Then calculatethe new area!

Change the lengths of a

square centimetre to millimetres. Then calculate

the new area!

Grade3/4

Volume = 10 x 10 x 10 Volume = 1000mm

3

Volume = 100 x 100 x 100 Volume = 1,000,000cm

3

Why?

Why?

Click formore examples

Converting units of volume

8

Cubic centimetres to cubic millimetres

Cubic metres to cubic centimetres

Change the lengths of a

cubic centimetre to millimetres.

Then calculatethe new volume

Change the lengths of a cubic metre

to centimetres.

Then calculatethe new volume

Grade5

Click formore examples

Combining ratios

9

Example 1 Answer

Example 2

Answer

First rearrangeto find the ratio

b:c

Then combinethe ratios

like before.

b is commonto both ratios. 10 is the lowest

common multipleof 5 and 2.

Make the b parts of the ratios 10.

Grade5

Click formore examples

Probabilities and ratio

10

Example

Answer

First change theprobability toa percentage.

Then subtract from

100% and share in the ratio 7:8.

This is because

probabilities mustadd up to 100%.

Grade2-5 Questions

Feel calmer and more prepared for your maths exam.We have all topics covered with 1000s of examples to practise.

12

3

4

5

6

78

9