1-(1/2)*1-(1/3)*(1-(1/4)*(1-(1/5))).
1-(1/2)*1-(1/3)*(1-(1/4)*(1-(1/5)))．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

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

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(1/4) * (4/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(1/3) * (4/5)</gadget>
<output>4/15 = around 0.266667</output>

<gadget id="calculator">1 - (1/2) - (4/15)</gadget>
<output>7/30 = around 0.233333</output>

<result>7/30 = around 0.233333</result>