You are fitting a new kitchen and measure the following lengths of pipe. Subtract the shortest length from the longest. 0.81 m 1.08 m 0.8 m 180 cm 18 cm

This requires converting the measurements which are in cm to m.

So you could have 180cm as 1.8m and 18cm as 0.18 (divide cm by 100 to get m)

Then you would take away the shortest, 0.18, from the longest, 1.8m to get

1.8 - 0.18 = 1.62