Add (2/5) to (5/6) of a number, and the sum is (5/8). Find this number.
一个数的(5/6)加上(2/5)，和是(5/8)，求这个数．
<gadget id="calculator">5 / 8</gadget>
<output>5/8 = around 0.625</output>

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

<gadget id="calculator">(5/8) - (2/5)</gadget>
<output>9/40 = around 0.225</output>

<gadget id="calculator">5 / 6</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">(9/40) / (5/6)</gadget>
<output>27/100 = around 0.27</output>

<result>27/100 = around 0.27</result>