A project can be completed by A alone in 12 days, B by himself in 18 days, and C by himself in 36 days. After working with 3 people for several days, B took a break due to illness, so that the entire project was completed on the 6th day, how many days did B rest?
一件工程，甲单独做12天完成，乙单独做18天完成，丙单独做36天完成．在3人合作，做了若干天后，乙因病中途休息，这样第6天才完成全部工程，问乙休息了几天？
<gadget id="calculator">1 / 12</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">(1/12) * 6</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 / 36</gadget>
<output>1/36 = around 0.027778</output>

<gadget id="calculator">(1/36) * 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">1 - (1/2) - (1/6)</gadget>
<output>1/3 = around 0.333333</output>

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

<gadget id="calculator">(1/12) + (1/18) + (1/36)</gadget>
<output>1/6 = around 0.166667</output>

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

<gadget id="calculator">6 - 2</gadget>
<output>4</output>

<result>4</result>