There are 45 students in class one of six years, girls account for (2/5), how many boys are there?
六年一班有学生45人，女生占(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">45 * (3/5)</gadget>
<output>27</output>

<result>27</result>