Measure objects in centimeters, step by step
A ruler only makes sense when every centimeter on the page is a real centimeter.
The question
Measure the toothbrush
start at:0
not at:the end of the ruler
read the far end:13
starts on:0
ends on:13
13 cm
- Line the object up with the 0, not with the end of the ruler. Every ruler has a little margin before its zero — measure from the end and the answer comes out a centimeter or two long, every time.
- Now follow the toothbrush to its far end and read the mark it stops on. Nothing is worked out here — the numbers along a ruler have already counted the centimeters from 0, so the mark at the end IS the measurement.
- So the toothbrush is 13 cm.
How it works.
- 01
Line the object up with the 0, not with the end of the ruler. Every ruler has a little margin before its zero — measure from the end and the answer comes out a centimeter or two long, every time.
- 02
Now follow the toothbrush to its far end and read the mark it stops on. Nothing is worked out here — the numbers along a ruler have already counted the centimeters from 0, so the mark at the end IS the measurement.
- 03
So the toothbrush is 13 cm.