Cut off a wire (4/7), how much is left
一根铁丝剪去(4/7)，还剩下多少
<gadget id="calculator">4 / 7</gadget>
<output>4/7 = around 0.571429</output>

<gadget id="calculator">1 - (4/7)</gadget>
<output>3/7 = around 0.428571</output>

<result>3/7 = around 0.428571</result>