The number of fifth-grade students in a certain school did not participate in the general cleaning (1/4). Later, two students took the initiative to participate, and the actual number of participants was the number of non-participants (1/3). Ask how many fifth-grade students there are in a certain school people?
某校五年级学生大扫除的人数是未参加的(1/4)，后来又有2个同学主动参加，实际参加的人数是未参加人数的(1/3)，问某校五年级学生有多少人？
<gadget id="calculator">3 + 1</gadget>
<output>4</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">4 + 1</gadget>
<output>5</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(1/4) - (1/5)</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">2 / (1/20)</gadget>
<output>40</output>

<result>40</result>