If x is a small negative integer and y is a large positive integer, which of the following expressions must be positive?

Before considering the answer choices, recall the properties of positive and negative integers. Both multiplication and division of a positive integer with a negative integer always yield a negative integer. Consequently, the only possible answer choice that must be positive is y − x.

An alternative solution is choosing a small negative integer for x, −1, and a large positive integer for y, 100, and substituting these values into each of the answer choices.