There are 280 girls in a certain school, and the number of girls is male (4/5). How many boys are there?
某校有女生280人，女生人数是男生的(4/5)．男生有多少人？
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">280 / (4/5)</gadget>
<output>350</output>

<result>350</result>