Measurement
Changing between units of measure
Change a measurement from a larger unit to a smaller one and back again, and add measurements written in mixed units.
The same length can be written in more than one way. A ribbon does not change when you call it 2 metres instead of 200 centimetres — only the words change, and the number changes with them. Measuring in a smaller unit always needs a bigger number, because it takes more small things to cover the same distance.
The three facts worth knowing by heart
There are 100 centimetres in 1 metres, 1,000 metres in 1 kilometres, and 1,000 g in 1 kg. Everything else in this skill is one of those three facts plus a multiplication or a division: larger unit to smaller, multiply; smaller unit to larger, divide.
Worked example
How many centimetres are there in 4 metres?
One metres is 100 centimetres.
That is the fact everything else hangs off.
Try it together
Now let us turn 2 metres and 35 centimetres into a single number together.
A measurement written in two units has to be brought into one unit before it can be added up.
1.First change the larger part across. How many centimetres are 2 metres?
Have a go
Have a go on your own. There are 1,000 g in 1 kg. How many g are there in 6 kg? Give just the number.
Hint: Six lots of a thousand.
Ready to practise?
Eight questions on what you have just read. Nothing is timed, and you can play as many times as you like.