A bag of cement, 40% is used, and the remaining part is 10 kg more than the used one, how many kg is used?
一袋水泥，用去40%，剩下的部分比用去的多10千克，用去了多少千克？
<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5) - (2/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">10 / (1/5)</gadget>
<output>50</output>

<gadget id="calculator">50 * (2/5)</gadget>
<output>20</output>

<result>20</result>