There are 95 students in the sixth grade of Aolin Primary School. The number of people participating in the mathematics invitational competition accounted for (2/5) of the whole grade, and there were 18 girls participating in the competition. What percentage of the boys in the whole grade take part in the mathematics invitational competition? (Click on the idea: find out the unit "1", and first find out the number of students participating in the mathematics invitational competition).
奥林小学六年级有学生95人．参加数学邀请赛的人数占全年级人数的(2/5)，其中参赛女生有18人．参加数学邀请赛的男生占全年级人数的几分之几？(思路点击：找准单位"1"，先求出参加数学邀请赛的学生数)．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">95 * (2/5)</gadget>
<output>38</output>

<gadget id="calculator">38 - 18</gadget>
<output>20</output>

<gadget id="calculator">20 / 95</gadget>
<output>4/19 = around 0.210526</output>

<result>4/19 = around 0.210526</result>