There are 20 boys in Class 5 and 1, and the number of girls is 4/5. How many girls are there?
五1班有男生20人，女生人数是男生的(4/5)，女生有多少人？
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">20 * (4/5)</gadget>
<output>16</output>

<result>16</result>