Завдання 301 - 400 » 343-344

343. Скороти дріб: 1) 25/40 = 5/8; 2) 60/75 = 4/5; 3) 154/182 = 11/13; 4) 105/399 = 5/19. 344. Обчисли: 1) 42/7 + 10/21 = 4(6 + 10)/21 = 416/21; 2) 55/12 + 711/15 = 12(25 + 44)/60 = 1269/60 = 139/60 = 133/20; 3) 72/5 – 44/15 = 3(6 - 4)/15 = 32/15; 4) 87/24 – 59/10 = 731/24 – 59/10 = 2(155 - 108)/120 = 247/120.