There is a rope that has been used for 25 meters and there are 15 meters left, how much of the rope is left.
有一根绳子用去了25米还剩下15米，剩下的占这根绳子的多少．
<gadget id="calculator">25 + 15</gadget>
<output>40</output>

<gadget id="calculator">15 / 40</gadget>
<output>3/8 = around 0.375</output>

<result>3/8 = around 0.375</result>