There are 42 students in Class 1, Grade 6, among which male students account for 4/7 of the total number of students in the class. Find the number of girls in this class.
六年级1班共有学生42名，其中男同学占全班学生数的(4/7)，求这个班级女生的人数．
<gadget id="calculator">4 / 7</gadget>
<output>4/7 = around 0.571429</output>

<gadget id="calculator">42 * (4/7)</gadget>
<output>24</output>

<gadget id="calculator">42 - 24</gadget>
<output>18</output>

<result>18</result>