To find the fraction of a whole pizza each person will get when Joshua is sharing half of a pizza with three friends (a total of four people), you need to divide the half pizza by the number of people.
The suitable expression from the provided options is:
1/2 ÷ 4 (1 half divided by 4)
This represents dividing the half of the pizza by the four people sharing it, which gives you the fraction of pizza each person will get.