Look at the corridor outside our classroom and the playground beyond the door. Which one is longer? How could we settle it without walking the whole way?

Watch as we hold a metre stick up against real things around our room — the board rail, a Maths book, the classroom door. Each time, look for an anchor you already know the length of, picture how many of it would fit, and say your estimate out loud. Then we measure it together to see how close we were.

Now we try it together with real classroom lengths: the teacher's desk, the width of the door frame, and the distance from the front of the room to the back wall. Write your estimate in your table first, then we measure each one with a metre stick and you fill in the actual and the difference.