You see a bargain in a shop for £97 but don’t have the money to buy it so you borrow £50
from one friend and £50 from another. (£50 + £50 = £100) You get £3 change, you give £1
to one friend and £1 to the other and keep a £1 yourself. This means that you now owe
each of your friends £49 but hang on... ( £49 + £49 = £98 ) plus the £1 you kept = £99..
Where is the missing pound?