Xiaoming, Xiaowen, and Xiaoyu are three students. Xiaoming is (7/20)m taller than Xiaowen, and Xiaoyu is (3/20)m taller than Xiaowen. How much is the difference in m between Xiaoming and Xiaoyu?
小明、小文、小宇三名同学，小明比小文高(7/20)m，小宇比小文高了(3/20)m，小明与小宇相差多少m？
<gadget id="calculator">7 / 20</gadget>
<output>7/20 = around 0.35</output>

<gadget id="calculator">3 / 20</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">(7/20) - (3/20)</gadget>
<output>1/5 = around 0.2</output>

<result>1/5 = around 0.2</result>