A Guide to the GRE/Integers

Integers Though not explicitly tested, the concepts of integers and whole numbers are important to solving GRE math problems. Rules 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. Practice Determine whether each of the following is an integer, a whole number, or neither. 1. -2 2. 113.7 3. 4. 593 Comments 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 Questions 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.