Among the fifth grade students, (1/2) students like music class, and 75% like physical education class. No one likes neither physical education class nor music class, so how many students like both physical education class and music class?
五年级学生，喜欢音乐课的同学占(1/2)，喜欢体育课的占75%，没有人既不喜欢体育课又不喜欢音乐课，那么既喜欢体育课又喜欢音乐课的占多少．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">75 / 100</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">(3/4) - 1</gadget>
<output>-1/4 = around -0.25</output>

<gadget id="calculator">(1/2) + (-1/4)</gadget>
<output>1/4 = around 0.25</output>

<result>1/4 = around 0.25</result>