A bucket of water, use up (2/5) of it, and there are 15 kilograms left, how many kilograms does this bucket of water weigh?
一桶水，用去它的(2/5)，还剩15千克，这桶水重多少千克？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">15 / (3/5)</gadget>
<output>25</output>

<result>25</result>