In class 3, the number of people who participated in the manual group accounted for (4/5) of the whole class, and the number of people who participated in the technology group accounted for (2/5) of the whole class. What percentage of the number of people participated in both?
三1班参加手工组的人数占全班人数的(4/5)，参加科技组的人数占全班人数的(2/5)，两样都参加的人数占全班人数的几分之几？
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(2/5) - 1</gadget>
<output>-3/5 = around -0.6</output>

<gadget id="calculator">(4/5) + (-3/5)</gadget>
<output>1/5 = around 0.2</output>

<result>1/5 = around 0.2</result>