A project can be completed by A alone in 8 days and B by himself in 12 days. Now A and B will work together for 3 days, and A will do the rest alone. How many days will it take to complete?
一项工程，甲单独做8天完成，乙单独做12天完成．现在甲乙合做3天后，剩下的由甲独做，还需几天完成？
<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">1 / 12</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">(1/8) + (1/12)</gadget>
<output>5/24 = around 0.208333</output>

<gadget id="calculator">(5/24) * 3</gadget>
<output>5/8 = around 0.625</output>

<gadget id="calculator">1 - (5/8)</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">(3/8) / (1/12)</gadget>
<output>9/2 = around 4.5</output>

<result>9/2 = around 4.5</result>