Experimental Primary School celebrated the Science and Technology Festival and organized students to watch science and education films. The three films were screened for (9/2) hours, of which the first film was screened for (5/4) hours and the second film was screened for 1 hour. How many hours will the third film run? (column equation solution)
实验小学庆祝科技节，组织同学们观看科教片，三部影片共放映(9/2)小时，其中第一部影片放映(5/4)小时，第二部影片放映1小时．第三部影片放映多少小时？(列方程解答)
<gadget id="calculator">9 / 2</gadget>
<output>9/2 = around 4.5</output>

<gadget id="calculator">5 / 4</gadget>
<output>5/4 = around 1.25</output>

<gadget id="calculator">(9/2) - (5/4) - 1</gadget>
<output>9/4 = around 2.25</output>

<result>9/4 = around 2.25</result>