One of the symbols in the formula (1/2)+(2/5)+(3/4)+(1/8)=(39/40) is wrong. What is the correct formula?
算式(1/2)+(2/5)+(3/4)+(1/8)=(39/40)中有一个运算符号错了，正确的算式是多少．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

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

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

<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">(1/10) + (3/4) + (1/8)</gadget>
<output>39/40 = around 0.975</output>

<result>39/40 = around 0.975</result>