Suppose that you have a stack of pennies. If you want to know without counting whether there is an odd or even number of pennies, then you have to split them into two parts, for example, placing one coin left and one coin right.
If the number of pennies is even, then no coins will left, if the number is odd, then one coin will be extra.
83.21.....................
What you need to do is subtract 2 hours and 48 minutes from 4 hours and 25 minutes. Each hour is 60 minutes. 2 hrs and 48 min is 168 minutes, and 4 hrs and 25 min is 265 minutes. 265 subtract 168 is 97. That means the kids spent 1 hour and 37 minutes at the pool in the afternoon.
Your answer is going to be 8.33