Here is a number: 256. What is it really made of? How many hundreds are hiding in it? How many tens? How many units? Hands up and tell me one part you can see.

Look at the blocks for each number, shown as hundreds, tens and units. Each number is shown two ways. Look carefully at how many tens each one really holds.

Today we work through these numbers together on the board: 138, then 305, then 260, then 490. The zero in 305 catches people out, so we will say each part slowly before we check it.

Now for our challenge on the board. We will partition 172, then partition 508, then build 40 tens, then build 62 tens. The last two are the tricky ones: think about how many hundreds hide inside all those tens before you start building.