McGraw-Hill Education GRE 2019

Number Properties

Study this chapter to learn about:

■ Factors and multiples

■ Odds and evens

■ Positives and negatives

■ Evenly spaced sets

O

n a broad level, you can think of properties of numbers as the branch

of math concerned with how numbers behave in certain situations.

Though this is an enormous field in formal mathematics, the GRE

will be concerned with properties of numbers in the following

contexts: divisibility, odds and evens, positives and negatives, and evenly spaced

sets. Because these areas are all concerned with concrete mathematical rules and

what you can deduce from these rules, questions testing these concepts will often

appear in Quantitative Comparison questions or a “must be true” or “could be

true” format in Discrete Quantitative questions.

Factors and Multiples

Any whole number is an integer. For example, 2 and –9 are integers, but^32 and –7.2

are not. The factors (or divisors) of an integer are the integer values that divide

evenly into that number. 2 is a factor of 12 because^122 = 6, which is an integer. But

5 is not a factor of 12, because^125 = 2.4, which is not an integer. To determine the

factors of a number, you can create a factor table. For example, the factors of 12 are:

12

6

4

1

2

3

CHAPTER 9

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