Total number of slices = 12
No. of slices eaten by Kesh = 2
No. of slices eaten by Jorge = 3
No. of slices left
= Total number of slices - (No. of slices eaten by Kesh + No. of slices eaten by Jorge)
= 12 - (2 + 3)
= 12 - 5
= 7
Fraction of the pizza left
= No. of slices left/Total number of slices
= 7/12