How many different fractions can be formed by randomly choosing one of the numbers 5, 7, 9, 11, 13, and 17 as the numerator and one as the denominator.
在5、7、9、11、13、17这些数中任取一个做分子、一个做分母，可以组成多少个不小同的分数．
<gadget id="calculator">6 - 1</gadget>
<output>5</output>

<gadget id="calculator">6 * 5</gadget>
<output>30</output>

<result>30</result>