A list of groceries

A young boy stopped by the corner grocery store and read his list to the clerk: "10 pounds if sugar at £1.25 a pound; 4 pounds of coffee beans at £1.50 a pound; 2 pounds of butter at £1.10 a pound and 2 bars of soap at 83 pence each. How much does that come to?"

"Twenty-two pounds and thirty-six pence," replied the clerk.

"If I gave you three ten pound notes, how much change would I get?"

"Seven pounds and sixty-four pence."

With that the boy walked out saying:"Thanks! That's my arithmetic homework done for tomorrow."