No more than 50 students in a class. On Children's Day, the whole class (4/9) went to participate in the singing competition, the whole class (2/5) went to play table tennis, and the rest of the students went to the movies, so how many students watched movies? people.
某班人数不超过50人．"六一"儿童节那天全班学生的(4/9)去参加歌咏比赛，全班的(2/5)去打乒乓球，而其余的学生都去看电影，那么看电影的学生有多少人．
<gadget id="calculator">9 * 5</gadget>
<output>45</output>

<gadget id="calculator">4 / 9</gadget>
<output>4/9 = around 0.444444</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (4/9) - (2/5)</gadget>
<output>7/45 = around 0.155556</output>

<gadget id="calculator">45 * (7/45)</gadget>
<output>7</output>

<result>7</result>