There are a total of 104 students in the first and second grades. This semester, 2 students have transferred from each of the two grades. Now the ratio of the number of students in the second grade to the first grade is 11:9. How many original students are there in the first grade?
一、二年级共有学生104人，这学期两个年级各转走学生2人，现在二年级与一年级的人数比是11：9．一年级原有学生多少人．
<gadget id="calculator">2 * 2</gadget>
<output>4</output>

<gadget id="calculator">104 - 4</gadget>
<output>100</output>

<gadget id="calculator">11 + 9</gadget>
<output>20</output>

<gadget id="calculator">9 / 20</gadget>
<output>9/20 = around 0.45</output>

<gadget id="calculator">100 * (9/20)</gadget>
<output>45</output>

<gadget id="calculator">45 + 2</gadget>
<output>47</output>

<result>47</result>