Завдання 1101 - 1200 » 1139

Обчисли: 1) 2/9 – (–1/18) + 1/2 = 2/9 + 1/18 + 1/2 = (4 + 1 + 9)/18 = 14/18 = 7/9; 2) – 4/7 + 3/14 – 1/21 =– 4/7 + 3/14 + (–1/21) = – 24/42 + 9/42 + (–2/42) = – 17/42; 3) 1/6 – 3/8 – 5/12 + 2/3 = 1/6 + (– 3/8) + (– 5/12) + 2/3 = 4/24 + (– 9/24) + (– 10/24) + 16/24 = 1/24.