There are 18 boys and 9 girls in the aviation model group of a certain elementary school. What percentage of the total number of boys are there?
某小学航模组中，男生18人，女生9人，男生人数占总人数的几分之几？
<gadget id="calculator">18 + 9</gadget>
<output>27</output>

<gadget id="calculator">18 / 27</gadget>
<output>2/3 = around 0.666667</output>

<result>2/3 = around 0.666667</result>