rope is 12m long, cut (1/4) of the full length for the first time, and (1/2)m for the second time. How many m less is the cut off than the rest?
一条绳子长12m，第一次剪去全长的(1/4)，第二次剪去(1/2)m．剪去的比剩下的少多少m．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">12 * (1/4)</gadget>
<output>3</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">3 + (1/2)</gadget>
<output>7/2 = around 3.5</output>

<gadget id="calculator">12 - (7/2) - (7/2)</gadget>
<output>5</output>

<result>5</result>