The leaflet, called It All Adds Up, includes examples urging parents to teach maths to their children at the shops, in the supermarket and even when ordering a takeaway, which is where the problems start.
"VAT," says the leaflet, "is... charged at 17.5 per cent, which seems like a difficult amount to deal with. Actually it's easy."
The example tells parents to write down the cost of the item, for example fish and chips at pounds 2.60. Then work out 10 per cent (26p), halve it to get 5 per cent (13p) and halve it again for 2.5 per cent (7p). Finally, the triumphant parent can add the three together to get 17.5 per cent (46p). "So," continues the leaflet, "46p of the pounds 2.60 you spent on fish and chips was VAT!"
Unfortunately you can only work out the VAT in that way if you know the cost before the VAT was added. To work it out from the final price is an altogether more difficult sum.
Doug French, chairman of the Mathematical Association's teaching committee, said: "I have no problem with the Government giving out examples of how to do things - as long as they are right." The correct way to work out VAT, he said, was to divide the price by 1.175, thus giving the pre-VAT cost (a job best done with a calculator). So in this case the fish and chips cost pounds 2.60, which works out at pounds 2.21 plus VAT of 39p.Reuse content