class carries out extracurricular activities. (1/7) of the whole class participates in the science and technology group, which is less than that of the reading group (2/7). How much?
一班开展课外活动，全班人数的(1/7)参加科技组，比参加阅读组的少占全班人数的(2/7)，参加这两个组的人数占全班人数的几分之几？
<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">2 / 7</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">(1/7) + (2/7) + (1/7)</gadget>
<output>4/7 = around 0.571429</output>

<result>4/7 = around 0.571429</result>