Вправи 201 - 300 » 266

Знайдить значення виразу, попередньо скоротивши дроби: 1) 25/80 + 45/60 = 5/16 + 3/4 = (5 + 3 • 4)/16 = 17/16; 2) 20/45 + 26/54 = 4/9 + 13/27 = (4 • 3 + 13)/27 = 25/27; 3) 36/300 + 12/40 – 350/1000 = 3/25 + 3/10 – 7/200 = (3 • 8 + 3 • 20 - 7)/200 = 77/200; 4) 14/24 – 39/90 + 15/100 = 7/12 – 13/30 + 3/20 = (7 • 5 - 13 • 2 + 3 • 3)/60 = 18/60 = 3/10; 5) 42/120 + 20/30 – 28/160 = 7/20 + 5/8 – 7/40 = (7 • 2 + 5 • 5 - 7)/40 = 32/40 = 4/5; 6) 45/72 – 33/144 – 20/64 = 5/8 – 11/48 – 5/16 = (5 • 6 - 11 - 5 • 3)/48 = 4/48 = 1/12.