There are 20 girls in Class 61 and Class 62. The number of girls in Class 61 is the number of boys (6/5), the number of girls in Class 62 is the number of boys (5/7), how many fewer boys in Class 61 than boys in Class 62?
六一班和六二班的女生都是20人．六一班的女生人数是男生的(6/5)，六二班的女生人数是男生人数的(5/7)，六一班的男生比六二班的男生少多少人．
<gadget id="calculator">5 / 7</gadget>
<output>5/7 = around 0.714286</output>

<gadget id="calculator">20 / (5/7)</gadget>
<output>28</output>

<gadget id="calculator">5 / 6</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">20 / (5/6)</gadget>
<output>24</output>

<gadget id="calculator">28 - 24</gadget>
<output>4</output>

<result>4</result>