Why do this problem?
offers a context in which to think about relative size, and gives children chances to estimate quantities.
It might be appropriate to read the book "The Man" (by Raymond Briggs) with the class prior to working on this task.
Before looking at the problem specifically, it would be worth investigating how much liquid different everyday items hold, for example spoons, bowls, bottles and jugs. This practical exploration could be done in a water tray or simply a large bucket or bowl with small groups of learners.
Once the class comes onto looking at the questions, it is important that you encourage them to make estimations and explain how they arrived at their answer. It may be appropriate for you to share your own methods of estimating, particularly when it comes to the capacity of the man's mug. It would also be helpful to have a mug, ruler and measuring cylinder to hand so that everyone can check
whether their estimates are realistic.
How long is one centimetre? Ten centimetres? So how high do you think a mug might be?
How did you come up with your answer?
Can you think of anything that you know holds about a litre of liquid?
How much do you think a mug might hold?
You could challenge children to articulate the relationship between the relative size of the man and one of them. Is the man about twice as small as us? Five times smaller? Ten times smaller? Will this relationship hold for everything?
Some learners might find it helpful to have a series of tasks which requires them to estimate and then measure concrete items in the classroom before going on to estimate measurements of items they are visualising.