There are 60 students in class 601, the number of boys is the whole class (7/12), and several girls are transferred. At this time, the number of girls is the whole class (4/9). How many girls have been transferred?
601班有学生60人，男生人数是全班的(7/12)，又转来了几名女生．这时女生的人数是全班的(4/9)．又转来了几名女生？
<gadget id="calculator">7 / 12</gadget>
<output>7/12 = around 0.583333</output>

<gadget id="calculator">4 / 9</gadget>
<output>4/9 = around 0.444444</output>

<gadget id="calculator">1 - (4/9)</gadget>
<output>5/9 = around 0.555556</output>

<gadget id="calculator">(7/12) / (5/9)</gadget>
<output>21/20 = around 1.05</output>

<gadget id="calculator">60 * (21/20)</gadget>
<output>63</output>

<gadget id="calculator">63 - 60</gadget>
<output>3</output>

<result>3</result>