The number of students in the three classes of the sixth grade of Beijing Road Primary School is 45. The number of boys in Class 1 is the same as the number of girls in Class 2. The number of boys in Class 3 accounts for 60% of the whole class. How many girls are there in Grade 6? ?
北京路小学六年级三个班的人数都是45人，六1班的男生人数与六2班女生人数同样多，六3班的男生人数占全班人数的60%，六年级共有女生多少人？
<gadget id="calculator">60 / 100</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (3/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">45 * (2/5)</gadget>
<output>18</output>

<gadget id="calculator">45 + 18</gadget>
<output>63</output>

<result>63</result>