A project can be completed in 10 days alone, and B can be completed in 8 days alone. After the two teams work together for one day, how much of the project is left.
一件工程，甲独做10天可以完成，乙独做8天可以完成，两队合做一天后，剩下这项工程的多少．
<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

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

<gadget id="calculator">(1/10) + (1/8)</gadget>
<output>9/40 = around 0.225</output>

<gadget id="calculator">1 - (9/40)</gadget>
<output>31/40 = around 0.775</output>

<result>31/40 = around 0.775</result>