It takes 18 days for A to complete a project alone, and 12 days for B to complete it alone. Now B will do it in 2 days first, and then A and B will do it together. How many days can it be completed?
某工程甲单独做需18天完成，由乙单独做需12天完成，现在乙先做2天，再甲、乙合做，问合做几天可以完成？
<gadget id="calculator">1 / 12</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">(1/12) * 2</gadget>
<output>1/6 = around 0.166667</output>

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

<gadget id="calculator">1 / 18</gadget>
<output>1/18 = around 0.055556</output>

<gadget id="calculator">(1/18) + (1/12)</gadget>
<output>5/36 = around 0.138889</output>

<gadget id="calculator">(5/6) / (5/36)</gadget>
<output>6</output>

<result>6</result>