How do you 'convert into the same units'?

Children learn about measuring weight, capacity (volume of liquid) and length throughout their time at primary school.

Children in upper Key Stage 2 will often need to solve word problems involving measures that require them to convert one measurement so that both measurements are in the same unit, for example:

I am 1.2m tall. My sister is 85 cm tall. How much taller am I than my sister?

Usually, a child would convert 1.2m to 120 cm and then would easily be able to work out the difference between 85cm and 120cm (which is 35cm).

In Year 6, children need to convert between units using decimals to three places, so they may come across a problem like the following:

I have 2.45 litres of orange juice. I pour 500ml of orange juice out and drink it. How much do I have left?

To work this out, it is likely a child would need to convert 2.45 litres to 2450ml, then subtract 500ml from this to make 1950ml.

In Year 6 children might also be asked to convert between imperial and metric units of measurement.

Children need a lot of practice with converting units of measurement. There can be some confusion over the fact that grams and millilitres deal in thousands and centimetres deal in hundreds. It is a really good idea for children to become confident with how many millilitres, grams and centimetres are in a litre, kilogram and metre in Year 4. (This may need lots of testing, little and often!)