A gardener owns an old, petrol-driven mower. It has a fuel tank with a capacity of half a gallon. How many centilitres is this? (1 gallon ≈ 4.5 litres)

If 1 gallon = 4.5 liters, then 1/2 a gallon will equal half of 4.5 liters ... which = 2.25 liters

1 liter = 100 centiliters ... so 2.25 liters = (2.25 * 100) = 225 centiliters <=