How many minutes in an hour? So how many litres does it pump in an hour? How many hours in a day? So how many litres does it pump in a day? Keep going in the same way - how many days in a year?

How many times does the heart beat in an hour? How many in a day? The crucial fact here is to know how many days there are in a leap year.

How would you write half a million in digits? So how many days is this? And therefore how many years?