Among (5/12), (5/21), (7/12), 1, what is the smallest
在(5/12)、(5/21)、(7/12)、1中，最小的是多少
<gadget id="calculator">5 / 21</gadget>
<output>5/21 = around 0.238095</output>

<result>5/21 = around 0.238095</result>