How do we measure objects?
Length is how long or tall something is. It is usually measured in centimetres (cm) and metres (m).
If you draw a line on a piece of paper, you could measure that line with a ruler. If you take a look at a ruler you will see it measures in centimetres (cm).
If you wanted to measure your kitchen table, you wouldn’t use a ruler. It would be much easier to use a tape measure. If you look at a tape measure you will see it measures in centimetres (cm) and metres (m). 
Smaller objects are normally measured in cm.
Larger objects are normally measured in m.
Your kitchen table is bigger or greater than the line on the paper.
Example 1:
Which of these measurements is the longest?
3 cm, 9 cm, 20 cm, 14 cm
Answer: 20 cm
Example 2:
Which of these measurements is the shortest?
13 m, 24 m, 5 m, 8 m
Answer: 5 m
