Dig a canal, team A digs this canal every day (1/10), and team B digs this canal every day (1/15). If Team B digs alone for 5 days, and Team A joins in to dig together, how many days will it take to complete the canal?
挖一条水渠，甲队每天挖这条水渠的(1/10)，乙队每天挖这条水渠的(1/15)．如果乙队单独挖5天后，甲队加入一起挖，挖完这条水渠一共要用多少天？
<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">(1/15) * 5</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(1/10) + (1/15)</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">(2/3) / (1/6)</gadget>
<output>4</output>

<gadget id="calculator">4 + 5</gadget>
<output>9</output>

<result>9</result>