There are 54 students in Class 61, among which girls account for 4/9 of the whole class, how many boys are there?
六一班有学生54人，其中女生占全班人数的(4/9)，男生有多少人．
<gadget id="calculator">4 / 9</gadget>
<output>4/9 = around 0.444444</output>

<gadget id="calculator">1 - (4/9)</gadget>
<output>5/9 = around 0.555556</output>

<gadget id="calculator">54 * (5/9)</gadget>
<output>30</output>

<result>30</result>