A job needs to be completed by 1 person in 40 hours. It is planned that 2 people will do it in 4 hours first, and the rest of the work will be completed in 8 hours. How many more people are needed?
一项工作，由1人做要40小时完成，要计划由2人先做4小时，剩下的工作要在8小时完成，问还需增加几人？
<gadget id="calculator">1 / 40</gadget>
<output>1/40 = around 0.025</output>

<gadget id="calculator">(1/40) * 2 * 4</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(4/5) / 8 / (1/40)</gadget>
<output>4</output>

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

<result>2</result>