There are 40 students in Class 5 and 2, including 18 girls, how many boys account for the whole class.
五2班有40人，其中女生18人，男生占全班人数的多少．
<gadget id="calculator">40 - 18</gadget>
<output>22</output>

<gadget id="calculator">22 / 40</gadget>
<output>11/20 = around 0.55</output>

<result>11/20 = around 0.55</result>