Notice that when x = 0 and y = 0, we have x - y = y-x. Does this show that there is a commutative for a subtraction? No. An example does not show that there is a general property,
Yes. The commutative property only needs to work sometimes.

d. vertex

step-by-step explanation:

question: how many people can she serve?

answer: she can serve 16.66666667 people. so she can only give 16 people a complete serving.

question: does she have enough ice cream for her guests?

answer: no. explanation: she only has enough for 16 people to have a full serving. however, she can give a 17th person a partial serving.