1) 8/14 = 4/7; 7/63 = 1/9; 30/84 = 5/14; (34·12)/(3·17) = (2·4)/(1·1) = 8/1 = 8.
3) a) 11/12 - y =11/24; y = 11/12 - 11/24 = (11·2-11)/24 = 11/24; y = 11/24
b) 5,86m + 1,4m = 76,23; 7,26m = 76,23; m = 76,23/7,26 = 7623/726 = 10,5; m = 10,5.
4) 1) 9/20 + 1/15 = (9·3 + 4)/60 = 31/60 пути прошёл за вторые сутки
2) 9/20 + 31/60 = (9·3 + 31)/60 = 58/60 = 29/30 пути прошёл за двое суток.
5) 6/9; 17/45; 11/18; 61/90