Here is a long line that runs from 0 all the way to 1,000, with a mark at every hundred. Now imagine I point to a spot that is a little bit past the middle. Roughly what number do you think is hiding there? Is it nearer 500 or nearer 600? Hands up and tell me which landmark you would look at first.

Watch each number land on the 0 to 1,000 line. Notice which landmark it sits near, and how that helps us place it without counting every step.

Now we place some numbers together on the board. Today we work through these numbers, in this order: 300, then 550, then 820, then 60. Each one gives us something new to think about. For each number, we find the two hundred marks it sits between first, then we decide which mark it hugs. Watch 550 carefully, because it lands right beside the halfway point.

Now we take turns placing four numbers, and each one is a little trickier than the last. In order: 150, then 480, then 615, then 940. Before each reveal, predict which two hundred marks it will sit between. Watch 480, because it lands just before the halfway mark and it is easy to nudge too far to the right.