In this activity, we will use what we know of scale and proportion to find a best buy product.

If we buy a tin of beans for £1 we know that if we want any more, we multiply by £1.

For example, 3 tins = 3 x £1 = £3

Simple!

Sometimes, there are offers which make some deals cheaper.

You have probably seen some, such as *Buy one get one free*, or *10% off if you buy 2*, or *Buy one and 2nd one half price*.

We are going to look at several ways of buying products and finding the cheapest or best value!

Before we look at the example, the aim of the game is to **make them the same number in order to compare them.**

We cannot compare a pack of 5 with a pack of 16 - we need the price for 1 or the same number.

**Example - non calculator**

Burgers are sold in boxes of **4 for £2.50** and boxes of **12 for £7.90**

Which size box is the best value?

**Answer**

We have to compare them and we cannot use a calculator, so we need to make it an easy number to compare!

**4 burgers = £2.50 12 burgers = £7.90**

If we multiply the 4 burger box by 3, that will give us the price for 12 and we can compare.

4 burgers x 3 = 12 burgers.

Therefore, **£2.50 x 3 = £7.50**

So, if we buy three boxes of 4 burgers, we can get 12 burgers for only £7.50.

If we buy the 12 burgers in just the one box of 12, it will cost us £7.90.

Buying the small box of 4 is clearly better value!

**Example - calculator**

Cartons of milk are sold in two sizes:

**Small - 1.2 litre = £1.40**

**Large - 3.5 litre = £3.99**

Which size is the best value?

**Answer**

As we can use a calculator for this, we can work out the** price of each for 1 litre**.

**Small - £1.40 ÷ 1.2 l = £1.166666....... per litre**

**Large - £3.99 ÷ 3.5 l = £1.14 per litre**

We can see that the **large carton** is better value!

Let's try some questions!