Use your hand span to measure the distance around a tree trunk. If
you ask a friend to try the same thing, how do the answers compare?
This article, written for students, looks at how some measuring units and devices were developed.
Can you put these shapes in order of size? Start with the smallest.
Can you use your fingers to show how long 18mm is approximately? Which
thing is about this length on the list?
How tall are you? How much do you weigh?