The mystical world of horses, bookmakers and horse racing in general revolves around the central theme of betting - and more specifically the odds on a particular horse.

Imagine that you decide to stake £4 of your "hard earned cash" on your favourite horse "Donkey Dong" and you stroll into the betting shop, look at the screen for your race and find that the "odds" are 6/4 - what on earth does that mean?

6/4 is called "six to four against" and means that if you bet £4 and your horse wins, then you will receive £10 - £6 winnings plus your £4 stake returned to you.

Now, if you bet £8 how much do you win if your nag comes romping home? Well, as you are betting twice as much money, you get twice as much back i.e. £12 plus your original stake of £8 which gives you a grand total of £20.

Of course, the reality is normally that you end up with £-4 or if you were foolish enough to bet £8, you end up with £-8!

Odds work in a similar way to mathematical ratios. Consider this example:

You are working for a building firm and call in at the suppliers for 35 paving slabs, you notice that they are priced up as £8.50 for 5. The supplier (Honest Joe) tells you that he'll give you 37 for the special price of £65. Do you pay him they money - or try to work out whether you're being done or not?

If 5 slabs cost £8.50, they can be expressed as a ratio as;

5 : 8.50

The first question to ask yourself is "How much does 1 slab cost?". You can work this out by simply dividing £8.50 by 5 = £1.70.

Now you need to know much 35 slabs are, simply multiply £1.70 by 35 = £62.90.

Easy isn't it - and by doing a little maths you've just managed you save yourself £2.10, which is not bad for a small amount of time spent doing a calculation.

Ratios are used more often in everyday life than you would think. If you are cooking and the recipe says that when making a cake to feed four people, you need to mix 4 parts flour to 2 parts margarine this is also a ratio 4 : 2. What do you do if you need to make a cake to feed 12 people?

If the ratio of 4 : 2 will feed 4 people then you need to multiply each number in the ratio (remember the proportional bit) by 3 (3 x 12 = 12), hence this give you a ratio of 12 : 6 i.e. 12 parts of flour to 6 parts of margarine.

Scales on maps use ratios - the Ordnance Survey 1 : 50,000 series says that the map is 2cm to 1km (see if you can work out where the 1 : 50,000 comes from - you need to know that 1m = 100cm).

Modellers and designers need to create smaller objects than in real life so they use ratios to scale them down. Interior designers plan arrangements of furniture etc. using a scale drawing - it's important to get these scales (ratios) right or you'll end up trying to squeeze a 140cm cupboard into a 120cm gap in the wall!

Ratios can present themselves in all sorts of ways, for example:

Consider you are a TV researcher and have conducted a survey from a group people and found that their preferred TV soap operas out of 3 choices (Eastenders : Coronation Street : Emmerdale) were in the ratio 5 : 6 : 4. Out of a group of 120 people, how many people watch Emmerdale?

To work this out add up all the numbers in the ratios 5 + 6 + 4 giving 15.

Now divide 120 (total number of people) by 15 giving 8

Now multiply 8 by 4 giving 32 which is the number of people watching Emmerdale.

(also 8 x 5 = 40 watch Eastenders and 8 x 6 = 48 watch Coronation Street)

MAKING RATIOS EVEN EASIER

You can simplify ratios in the same way as you can simplify fractions. e.g.

15 : 12 can be simplified by finding the largest whole number which can be divided into both 15 and 12 - it happens to be 3 , do the division and this leaves you with 5 : 4 which is easier to picture but proportionally exactly the same as the ratio 15 : 12.