There are 40 students in a class of three years, and the number of girls accounts for 2/5 of the whole class. How many boys are there?
三年一班有学生40人，其中女生人数占全班人数的(2/5)，男生有多少人？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">40 * (3/5)</gadget>
<output>24</output>

<result>24</result>