m and n are reciprocals of each other, then ((m)/5)*((n)/3)=how much.
m和n互为倒数，那么((m)/5)*((n)/3)=多少．
<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<result>1/15 = around 0.066667</result>