As a result of a math competition, among the students in a certain class, (1/7) were excellent, (2/3) were good, and the rest were average or poor. It is known that the number of students in the class is between 40 and 50, and the students who are average or poor how many people.
一次数学竞赛结果，某班学生中有(1/7)得优，(2/3)得良，其余得中或差，已知全班人数在40与50之间，得中或差的学生有多少人．
<gadget id="calculator">7 * 3 * 2</gadget>
<output>42</output>

<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">(1/7) + (2/3)</gadget>
<output>17/21 = around 0.809524</output>

<gadget id="calculator">1 - (17/21)</gadget>
<output>4/21 = around 0.190476</output>

<gadget id="calculator">42 * (4/21)</gadget>
<output>8</output>

<result>8</result>