Here is a number that looks tiny but has a real job to do: 0.001. Where would it sit on a number line? And why is it so small compared to numbers we usually write?

Take a good look before any hands go up.

We already know tenths and hundredths — today we go one step smaller, to thousandths, the third place. The flat is 1, the rod is 0.1, the small cube is 0.01, and the tiniest cube is 0.001. Watch each number build on the interactive and read the columns with me.

Now we build some ourselves. Today we work through these numbers together on the mat: 0.008, then 0.056, then 0.302, and finally 1.204. The zeros are the tricky part, so we'll say each column aloud before we add a block.

Time to read some numbers carefully. Together we'll build and check these on the mat: 0.003, then 0.027, then 0.105, then 1.008, and last of all 2.305. Each one is a little bigger, and the zeros are the ones that catch people out, so say the columns before you tap.