Here is a metre stick lying beside a short 30 cm ruler. If I laid the short ruler along the metre stick, it would only fit about three times. But how many single centimetre marks do you think fit all the way along the whole metre stick? Have a good guess before we check.

Look at the conversion ladder on the screen. The metre rung sits at the top and the centimetre rung below it, with a jump of one hundred between them. As each length is shown, notice that one hundred is added on for every whole metre.

Now watch a length that has metres and centimetres together.

And here is a longer mixed length, two whole metres with fifty centimetres left over.

A classmate will work each one at the board, and we will all read the pair aloud before we check. Watch the hundred pattern build each time.

Today we rename these lengths together:

• 1 m
• 2 m
• 4 m 20 cm
• 250 cm (the other way, we work this one on the board, splitting 250 into whole hundreds and a leftover)

Now we fill each rung to rename these lengths on the board. Watch for the hundred each metre adds, and for where the leftover centimetres join on.

• 1 m
• 3 m
• 4 m 20 cm
• 250 cm (the other way, from centimetres back to metres)