A cuboidal storage tank measures 2.5 m by 1.6 m by 1.2 m internally. How many litres of water does it hold when completely full? (1 cubic metre = 1000 litres.)

The tank holds $2.5\times 1.6\times$ 1.2 = 4.8 cubic m, and each cubic metre is 1000 litres, so the capacity = 4800 litres. The trap 4.8 quotes cubic metres as though they were litres; 48000 multiplies by 10000, borrowing the square-metre conversion factor; 480 multiplies by only 100. As a check, 4.8 cubic m is 4800000 cubic cm, and 1000 cubic cm make a litre.