project is completed in 8 days alone, and B is completed in 12 days alone. During the process, A asks for 4 days off, and B asks for several days off. It takes 10 days from start to finish. How many days did you ask B to ask for leave?
一项工程，甲单独做8天完成，乙单独做12天完成，中途甲请假4天，乙请假若干天，从开工到完共用了10天．求乙请假了多少天．
<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">10 - 4</gadget>
<output>6</output>

<gadget id="calculator">(1/8) * 6</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">1 - (3/4)</gadget>
<output>1/4 = around 0.25</output>

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

<gadget id="calculator">(1/4) / (1/12)</gadget>
<output>3</output>

<gadget id="calculator">10 - 3</gadget>
<output>7</output>

<result>7</result>