1 kg (1/5) weighs the same as 2 kg ((())/(())); how many tons is more than 15 tons (2/3).
1千克的(1/5)和2千克的((())/(()))一样重；比15吨多(2/3)是多少吨．
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">15 * (2/3)</gadget>
<output>10</output>

<gadget id="calculator">15 + 10</gadget>
<output>25</output>

<result>25</result>