To fill the pool with water alone, it takes 2 hours for water pipe A and 3 hours for water pipe B: if the two water pipes are filled with water at the same time, how many hours can the pool be filled (2/3).
单独把水池的水注满，甲水管要用2小时，乙水管要用3小时：如果两水管同时注水，多少小时可以注满水池的(2/3)．
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

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

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">(1/2) + (1/3)</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">(2/3) / (5/6)</gadget>
<output>4/5 = around 0.8</output>

<result>4/5 = around 0.8</result>