1. Put the numbers in order
7, 8, 13, 42, 50, 91
Get rid of the numbers on each side
If we have the numbers shown then cross a number from each side
8, 13, 42, 50, 91
8, 13, 42, 50,
13, 42
Now we have 13 and 42
Now all you do is add them together and divide by 2