Look at this new pencil held against a ruler. Roughly how long do you think it is? Is it more or less than ten centimetres? Hold up a hand if you think more, and a hand if you think less.

Watch four objects being measured on the ruler. Each time, notice where the object starts and which mark its far end reaches. Why do we always begin at zero?

Let's read the length of the object on the ruler together. Before anyone reads the far mark, we'll check the zero is lined up with one end. One pupil at a time will come up and read the object on the board to the nearest centimetre; everyone else watches the board and gets ready to say whether they agree.

Before you measure at your desks, watch one worked example of measuring to the nearest centimetre when the end does not land on a mark.

A glue stick is lined up with zero. Its far end sits between 7 and 8, a little closer to 8. The nearer centimetre is 8, so we record 8 cm.

Now measure five real objects on your own desk with your own ruler. Work through it in three clear steps:

1. First, estimate all five in your head: your rubber, your glue stick, the short side of your copybook, your pencil, and one object from the front desk that looks close to 10 cm.
2. Then measure all five, one at a time, to the nearest centimetre. Line the zero up with one end every time. If the far end sits between two marks, choose the nearer centimetre (halfway or past, round up).
3. Last, put your five lengths in order, shortest first.

Today you learned to:

• Estimate a length first, then measure it to the nearest centimetre.
• Line the zero up with one end and read the centimetre mark at the other end.