1)вычислите сумму 11\30+7\12 , 1\27+5\18, 1\6+1\10+1\15, 3\7+1\6+5\14, 5\12+2\9+1\18, 1\27+5\18, 3\7+1\6+5\14 , 1\2+1\3+1\9

Вычислим сумму дробей:

• 11\\30 + 7\\12  =  (11 * 2 + 7 * 5)/60 = (22 + 35)/60 = 77/60;
• 1\\27 + 5\\18 = (1 * 2 +  5 * 3)/54 = (2 + 15)/54 = 17/54;
• 1\\6 + 1\\10 + 1\\15 = (1 * 5 + 1 * 3 + 1 * 2)/30 = (5 + 3 + 2)/30 = 10/30 = 1/3; 
• 3\\7 + 1\\6 + 5\\14 = (3 * 6 + 1 * 7 + 5 * 3)/42 = (18 + 7 + 15)/42 =  (30 + 10)/42 = 40/42 = 20/21;
• 5\\12 + 2\\9 + 1\\18 = 5/12 + (2 * 2 + 1 * 1)/18 = 5/12 + 5/18 =   (5 * 3 + 5 * 2)/36 = (15 + 10)/36 = 25/36;
• 1\\27 + 5\\18 = 17/54; 
• 3\\7 + 1\\6 + 5\\14  = 20/21; 
• 1\\2 + 1\\3 + 1\\9 = (1 * 9 + 1 * 6 + 1 * 2)/18 = (9 + 6 + 2)/18 = 17/18.