There are 20 boys in Class 1 of the sixth grade in a certain elementary school, exactly 80% of the number of girls. How many students are there in the sixth grade?
某小学六年级一班有男生20人，正好是女生人数的80%，六年级一共有多少人？
<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">20 / (4/5)</gadget>
<output>25</output>

<gadget id="calculator">25 + 20</gadget>
<output>45</output>

<result>45</result>