Quantitative Comparison Problems on the GRE — Basic Math
On the GRE Math test, Quantitative Comparison problems cover a wide range of subjects. For example, even a basic math question might require you to be familiar with prime numbers, factors, multiples, and absolute values.
In a Quantitative Comparison question, the problem lists Quantity A and Quantity B, which can be numbers, variables, equations, words, figures, and so on. Your job is to compare these two quantities and determine whether one is greater, they’re equal, or the relationship can’t be determined.
The following practice questions require you to compare prime factors and absolute values.
Practice questions

Which quantity is greater?
A: The greatest prime factor of 36
B: The greatest prime factor of 48
A. Quantity A is greater.
B. Quantity B is greater.
C. The quantities are equal.
D. It cannot be determined from the information given.

Which quantity is greater?
A: –3 + –2
B: –3 + (–2)
A. Quantity A is greater.
B. Quantity B is greater.
C. The quantities are equal.
D. It cannot be determined from the information given.
Answers and explanations

C. The quantities are equal.
Prime factors of 36 are 3 and 2. Prime factors of 48 are 3 and 2 also. The greatest prime factor in both cases is 3. Choice (C) is the correct answer.

A. Quantity A is greater.
Absolute value means how far a number is from 0.
Thus, Quantity A is greater, making the correct answer Choice (A).