The numerator of a fraction is the product of two numbers that are reciprocals of each other, and the denominator is the largest prime number within 20. What is this fraction?
一个分数的分子是互为倒数的两个数的积，分母是20以内最大的质数，这个分数是多少？
<gadget id="calculator">1 / 19</gadget>
<output>1/19 = around 0.052632</output>

<result>1/19 = around 0.052632</result>