A guy and a girl play a game where they roll a dice. If the guy rolls an even number, the girl pays him that amount. If he rolls an odd number he pays her that amount.

The expected value is supposedly $0.5. ie mean of -1+2-3+4-5+6

but if i split the values like so

girl: 1,3,5 total = 9 Average is 9/3 = 3

guy: 2,4,6 total = 12 Average = 12/3 = 4

dif = 1 and not 0.5

why can i not split up their winnings like the above?

Thanks for your help