A Guide to the GRE/Integers
Though not explicitly tested, the concepts of integers and whole numbers are important to solving GRE math problems.
An integer is a number without any fraction or decimal behind it.
1, 3, -5, and 268 are integers, while 1.77 and are not.
A whole number is a non-negative integer.
0, 1, 2, and 3 are whole numbers; .62, -8, and are not.
Determine whether each of the following is an integer, a whole number, or neither.
The GRE isn't going to ask questions such as “which of the following is an integer?” but the concept is important for solving other questions. For instance, if 1 < x < 5, x could have an infinite number of values, from 1.00001 to 3.0065. But if x is an integer, its values are now limited to 2, 3, and 4.
Answers to Practice QuestionsEdit
1. -2 is an integer – it does not end in a fraction or decimal. However, it is not a whole number. Whole numbers are positive.
2. 113.7 is not an integer because it ends in a decimal. Because it is not an integer, it is not a whole number either. Remember, whole numbers are positive integers.
3. is not an integer – it is a fraction. Integers, remember, are numbers which do not end in fractions or decimals. Because it is not an integer, it is not a whole number either, since whole numbers are positive integers.
4. 593 is an integer because it does not end in a decimal. It is also a positive (non-negative) integer so it is also a whole number. Remember, all whole numbers are integers but not all integers are whole numbers, only if they are non-negative.