Converting Units Within a System Worksheets

Sample problems

1. Convert to the smaller unit: 3 km to m, 2 kg to g, 4 l to ml, 0.75 kg to g.
2. Convert to the bigger unit: 3000 m to km, 1500 g to kg, 250 ml to l, 6 mm to cm.
3. Convert 2.5 km to metres, and then to centimetres.
4. A child converts 2.5 km to metres by writing 2.5000. Explain why this converts nothing.

Common mistakes to watch for

• Answered 1500000 g-worth for the first, or 0.4000 and 3.2000 for the others — zeros appended rather than digits moved. 0.4000 is the same amount as 0.4, so nothing was converted.
• Answered 1.2 ml or 1200 l — the arithmetic right and the unit carried over from the wrong line. Saying roughly what the answer should be first (a bit over a litre) catches it.
• Said Mia “should have divided”. Correct and it is the answer rather than a method — the item asks for a way to SPOT the error, and both the direction rule and picturing the answer work when a child cannot remember which operation to use.

The answer key explains each one, so you can tell what a wrong answer means.