It takes 20 days for team A to dig a cave alone, and 30 days for team B to dig alone. After 10 days of joint digging by the two teams, how many tasks are left to be completed?
挖一个山洞，甲队独挖要20天完成，乙队独挖要30天才完成，两队合挖10天后，还剩下多少任务没完成？
<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">1 / 30</gadget>
<output>1/30 = around 0.033333</output>

<gadget id="calculator">(1/20) + (1/30)</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">(1/12) * 10</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">1 - (5/6)</gadget>
<output>1/6 = around 0.166667</output>

<result>1/6 = around 0.166667</result>