Вправа 201 - 300 » 217

217. Виконай дії. a) 2 + 8/15 • 19/16 = 2 + (8•25)/(15•16) = 2 + (1•5)/(3•2) = 2 + 5/6 = 25/6; б) 15/12 • 2 + 4 • 11/18 + 11/9 • 11/4 = (17•2)/12 + (4•19)/18 + (10•5)/(9•4) = 17/6 + 38/9 + 25/18 = (51+76+25)/18 = 152/18 = 76/9 = 84/9; в) 22/11 • 7/8 – 6 • 1/5 = (24•7)/(11•8) – (6•1)/5 = 21/11 – 6/5 = (105-66)/55 = 39/55; г) 21/10 • 41/6 + 6 • 3/8 – 9/20 • 6 = (21•25)/(10•6) + (6•3)/8 – (9•6)/20 = (7•5)/(2•2) + 9/4 – 27/10 = (35+9)/4 – 27/10 = 44/4 – 2,7 = 11 – 2,7 = 8,3.