Age 16 to 18
Note that most of the ideas used here are typically covered at
school before the age of 16, although possibly in mathematics,
physics or chemistry.
In estimation questions don't be afraid to have a go with a guess
at some numbers in the problem and then to refine your estimate
after checking it makes some sort of sense.
Although there is no 'right' answer to an estimation, there are
good or bad estimates and sensible or over detailed
Think how you might make your estimation a good one, and think how
it makes sense to ignore certain complexities in particular