A shop sells bags of crisps in different size packs. There are 18 bags of crisps in a small pack (£4), 20 bags of crisps in a medium pack (£4.99) and 26 bags of crisps in a large pack (£6). Which size pack is the best value for money?

You can use the price of each pack and divide it by the number of bags of crips to get the price per packet, the one with the lowest price per packet will be the best value for money.

The small packet cost £4 or 400p (you can use either number in your calcuator, but remember if you choose to use £4, your answer will be in pounds)  and contains 18 bags of crisps. 400/18 is 22.2, this means that each bag costs 22.2p. If you choose to use pounds 4.00/18=0.222. You mutiply your answer by 100 to get the value in pence, therefore 0.222 is the same as 22.2p

The medium packet costs £4.99 (499p) and contains 20 bags of crisps. 499/20 is 24.95p, or if you choose to use pounds, £4.99/20=0.2495, which is the same as 24.95p.

The large packet costs £6 (600p) and contains 26 bags of crisps. 600/26=23.08p, of if you choose to use pounds, 6/26=0.2308, which is the same as 23.08p.

As the small packet has the cheapest price per bag of crisps, it is th ebest value for money, followed by the large packet, and finally the medium packet, which is the worst value for money.