Three classes from my school were planning a visit to the cinema. When I finished taking the register, I asked if there was any money for the trip.
Three children came to the front, handed in their forms and paid Pounds 1.50 each. The third child handed his form in, but no cash.
"Where's your money?" I asked.
"My brother is paying Pounds 3 into the office for us both to go."
As my supervisor would soon be observing me teaching maths, I asked him what half of Pounds 3 was.