There are 21 boys in Class 51, 2 fewer than girls. What percentage of the whole class are boys?
五1班有男生21人，比女生少2人，男生人数占全班人数的几分之几？
<gadget id="calculator">21 + 2 + 21</gadget>
<output>44</output>

<gadget id="calculator">21 / 44</gadget>
<output>21/44 = around 0.477273</output>

<result>21/44 = around 0.477273</result>