Here are three digit cards: 3, 7 and 5. Using each card once, what is the very biggest three-digit number you could make? And what is the very smallest?

Have a think, then hands up. See if the number you make beats the person before you.

Here are three-digit numbers made from digit cards using place-value blocks. Notice where each card sits and how much it is worth in that column.

Now we build some together. For each set of digits, one pupil comes up to the board to build the number with the place-value blocks while the rest of the class watches and agrees or corrects aloud. We will make the biggest number and then the smallest number for each set: first 3, 7 and 5, then 8, 4 and 2, then 6, 3 and 1.

Before you build, say out loud which digit is the largest.

Now we take on four sets of cards, one at a time, and find the biggest and smallest three-digit number for each: first 2, 6 and 9, then 5, 1 and 4, then 7, 0 and 3 where the zero is the tricky one, and last of all 8, 8 and 1 where two cards are the same. Two cards can be the same, that is fine.

Before we build each set, hands up and say where each card must go.