A rope is 6m, how much m is left when (1/2) is used for the first time, and (1/4) is used for the second time.
一根绳子6m，第一次用去(1/2)，第二次用去(1/4)还剩多少m．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/2) - (1/4)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">6 * (1/4)</gadget>
<output>3/2 = around 1.5</output>

<result>3/2 = around 1.5</result>