There are 40 students in Class Six 1 of a certain school, which is 20% less than Class Six 2, and Class Six 3 is 25% more than Class Six 1. How many people are there in the three classes?
某校六1班有40人，比六2班少20%，而六3班比六1班多25%，三个班共有多少人？
<gadget id="calculator">20 / 100</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">40 / (4/5)</gadget>
<output>50</output>

<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 + (1/4)</gadget>
<output>5/4 = around 1.25</output>

<gadget id="calculator">40 * (5/4)</gadget>
<output>50</output>

<gadget id="calculator">50 + 50 + 40</gadget>
<output>140</output>

<result>140</result>