хелп люди
выполните действия 9/20+8/15 16/21-5/28 7/12-5/18+23/72

9/20 + 8/15 = 27/60 + 32/60 = 59/60,16/21 - 5/28 = 64/84 - 15/84 = 49/84 = 7/12,7/12 - 5/18 + 23/72 = 42/72 - 20/72 + 23/72 = 45/72 = 5/8