(1-((1/3)+(1/15)))/(4/5).
(1-((1/3)+(1/15)))/(4/5)．
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">(1/3) + (1/15)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(3/5) / (4/5)</gadget>
<output>3/4 = around 0.75</output>

<result>3/4 = around 0.75</result>