((2/5)-(1/6))/(1/30).
((2/5)-(1/6))/(1/30)．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">(2/5) - (1/6)</gadget>
<output>7/30 = around 0.233333</output>

<gadget id="calculator">1 / 30</gadget>
<output>1/30 = around 0.033333</output>

<gadget id="calculator">(7/30) / (1/30)</gadget>
<output>7</output>

<result>7</result>