The Metric system is so much easier than the old Imperial system, but there are still a few problems which come up when converting larger units to smaller units. Before attempting this certain facts need to be learnt off by heart, including;
10 mm = 1 cm
100 cm = 1 m
1000m = 1 km
1000 ml = 1l
1000g = 1 kg.
So writing 1.5 m in cm would entail multiplying 1.5 by 100, which equals 150 cm.
Converting 2.5 litres to ml would entail multiplying 2.5 by 1000 which equals 2500 ml.
This maths worksheet provides some practice with converting larger units to smaller units and can be found in our year 5 measures section.