There is a pile of cement, 4 tons have been used, and 20 tons are left. What fraction of this pile of cement was used?
有一堆水泥，用去4吨，还剩下20吨．用去的是这堆水泥的几分之几？
<gadget id="calculator">4 + 20</gadget>
<output>24</output>

<gadget id="calculator">4 / 24</gadget>
<output>1/6 = around 0.166667</output>

<result>1/6 = around 0.166667</result>