There are 15 boys and 13 girls in the interest group. How many girls account for the whole group?
兴趣小组有男生15人，女生13人，女生占全组人数的多少．
<gadget id="calculator">15 + 13</gadget>
<output>28</output>

<gadget id="calculator">13 / 28</gadget>
<output>13/28 = around 0.464286</output>

<result>13/28 = around 0.464286</result>