12/(1-(3/7))
12/(1-(3/7))
<gadget id="calculator">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">1 - (3/7)</gadget>
<output>4/7 = around 0.571429</output>

<gadget id="calculator">12 / (4/7)</gadget>
<output>21</output>

<result>21</result>