Вправа 201 - 300 » 258

258. Виконай дії: a) (18/13 : 33/13 + 5/7 : 8/21) : (81/8 + 31/2) = 19/93; 1. 21/13 : 42/13 = (21•13)/(13•42) = 1/2; 2. 5/7 : 8/21 = (5•21)/(7•8) = 15/8; 3. 1/2 + 15/8 = (4+15)/8 = 19/8; 4. 81/8 + 34/8 = 115/8 = 93/8; 5. 19/8 : 93/8 = (19•8)/(8•93) = 19/93; б) (284/5 : 135/7 + 63/5 : 2/3) : (111/16 : 21/4) = 16; 1. 144/5 : 96/7 = (144•7)/(5•96) = (12•7)/(5•8) = (3•7)/(5•2) = 21/20 = 2,1; 2. 33/5 : 2/3 = (33•3)/(5•3) = 9,9; 3. 2,1 + 9,9 = 12; 4. 27/16 : 9/4 = (27•4)/(16•9) = (3•1)/(4•1) = 0,75 = 3/4; 5. 12 : 3/4 = (12•4)/3 = 16.