Answer:
Order 5 pizza
1/2 pizza left over
Explanation:
Pizza is divided by 4 and each tudent get 1 part. So, one pizza is shared by 4 tudent.
18 tudent divide to group of 4
18/4 = 4group with 2 tudent remain
Total group = 4 + 1 remainder group = 5
Mary should order 5 pizza.
In the remainder group, there are 2 tudent. The pizza is divided by 4. Calculate the remaining pizza
4-2 = 2
2 out of 4 pizza left over. Simplify 2/4, you get 1/2 pizza.