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Rational numbers act rationally! What does that mean? In this case, acting rationally means that the decimal equivalent of the rational number behaves. The decimal eventually ends somewhere, or it has a repeating pattern to it. That’s what constitutes “behaving.”

Some rational numbers have decimals that end such as: 3.4, 5.77623, –4.5. Other rational numbers have decimals that repeat the same pattern, such as , or . The horizontal bar over the 164 and the 6 lets you know that these numbers repeat forever.

In all cases, rational numbers can be written as fractions. Each rational number has a fraction that it’s equal to. So one definition of a rational number is any number that can be written as a fraction, , where p and q are integers (except q can’t be 0). If a number can’t be written as a fraction, then it isn’t a rational number. Rational numbers appear in Chapter 16, where you see quadratic equations, and later, when the applications are presented.