(4/5)*((15/2)+(1/4)).
(4/5)*((15/2)+(1/4))．
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">15 / 2</gadget>
<output>15/2 = around 7.5</output>

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

<gadget id="calculator">(15/2) + (1/4)</gadget>
<output>31/4 = around 7.75</output>

<gadget id="calculator">(4/5) * (31/4)</gadget>
<output>31/5 = around 6.2</output>

<result>31/5 = around 6.2</result>