Вправи 201 - 300 » 283

Обчисліть значення виразу найзручнішим способом: 1) 5/18 + 4/81 + 7/18 + 5/81 =(5/18 + 7/18) + (4/81 + 5/81) = 12/18 + 9/81 = 2/3 + 1/9 = 6/9 + 1/9 = 7/9; 2) 9/40 + 13/50 + 12/50 + 11/40 = (9/40 + 11/40) + (13/50 + 12/50) = 20/40 + 25/50 = 1/2 + 1/2 = 1; 3) 7/16 + 11/42 + 9/16 + 17/42 = (7/16 + 9/16) + (11/42 + 17/42) = 16/16 + 28/42 = 12/3; 4) 117/24 + 31/36 + 54/24 + 28/36 = 11 + (17/24 + 4/24) + (1/36 + 8/36) = 11 + 21/24 + 9/36 = 11 + 7/8 + 3/12 = 11 + 21/24 + 6/24 = 1127/24 = 123/24 = 121/8.