There are 820 students in Mingde Primary School, among which girls account for 11/20 of the total number of students. How many boys are there in Mingde Primary School?
明德小学有学生820人，其中女生人数占学生总人数的(11/20)，明德小学有男生多少人？
<gadget id="calculator">11 / 20</gadget>
<output>11/20 = around 0.55</output>

<gadget id="calculator">1 - (11/20)</gadget>
<output>9/20 = around 0.45</output>

<gadget id="calculator">820 * (9/20)</gadget>
<output>369</output>

<result>369</result>