There are 54 students in class A, the number of students in class A is more than that of class B (2/7), how many students are there in class B?
甲班有学生54人，甲班的学生人数比乙班多(2/7)，乙班有多少人．
<gadget id="calculator">2 / 7</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">1 + (2/7)</gadget>
<output>9/7 = around 1.285714</output>

<gadget id="calculator">54 / (9/7)</gadget>
<output>42</output>

<result>42</result>