There are two classes A and B in the sixth grade. The number of students in class A is that of class B (5/7). How many students are there in the class?
六年级有甲、乙两个班，甲班学生人数是乙班的(5/7)，如果从乙班调3人到甲班，甲班学生人数就是乙班的(4/5)，甲班原有学生多少人．
<gadget id="calculator">5 + 7</gadget>
<output>12</output>

<gadget id="calculator">7 / 12</gadget>
<output>7/12 = around 0.583333</output>

<gadget id="calculator">4 + 5</gadget>
<output>9</output>

<gadget id="calculator">5 / 9</gadget>
<output>5/9 = around 0.555556</output>

<gadget id="calculator">(7/12) - (5/9)</gadget>
<output>1/36 = around 0.027778</output>

<gadget id="calculator">3 / (1/36)</gadget>
<output>108</output>

<gadget id="calculator">5 / 12</gadget>
<output>5/12 = around 0.416667</output>

<gadget id="calculator">108 * (5/12)</gadget>
<output>45</output>

<result>45</result>