(2/5)*(1/4)+(1/2)/(5/8).
(2/5)*(1/4)+(1/2)/(5/8)．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

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

<gadget id="calculator">(2/5) * (1/4)</gadget>
<output>1/10 = around 0.1</output>

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

<gadget id="calculator">5 / 8</gadget>
<output>5/8 = around 0.625</output>

<gadget id="calculator">(1/2) / (5/8)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(1/10) + (4/5)</gadget>
<output>9/10 = around 0.9</output>

<result>9/10 = around 0.9</result>