There are 6 tons of stones, take away (1/3), how many tons are left? how many tons
有6吨石头，运走(1/3)，还剩多少吨？多少吨
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">6 * (2/3)</gadget>
<output>4</output>

<result>4</result>