5. Все действия с обыкновенными дробями 1). (5/14 + 17/42) - 1 6/8 =

1) (5/14 + 17/42) - 1 6/8 = (15/42 + 17/42) - 1 3/4 = 32/42 - 7/4 = 16/21 - 7/4 = 64/84 - 147/84 = -83/84 2) (5/9 : 1 17/36 + 1/4) * 5/21 = (5/9 : 53/36 + 1/4) * 5/21 = (5/9 * 36/53 + 1/4) * 5/21 = (4/53 + 1/4) * 5/21 = (16+53)/212 * 5/21 = 69/212 * 5/21 = 23/212 * 5/7 = 115/1484 3) (2 1/4 + 4 5/6) : 2/3 - 3/5 = (9/4 + 29/6) : 2/3 - 3/5 = (27/12 + 58/12) * 3/2 - 3/5 = 85/12 * 3/2 - 3/5 = 85/8 - 3/5 = 425/40 - 24/40 = 401/40 = 10 1/40 4) (3 1/4 + 3 5/6) : (5 3/4 - 3 2/3) = (39/12 + 46/12) : (69/12 - 44/12) = 85/12 : 25/12 = 85/25 = 17/5 = 3 2/5 5) (6 4/5 - 2 3/4) : (2 16/21 + 3 2/3) = (136/20 - 55/20) : (58/21 + 77/21) = 81/20 : 135/21 = 81/20 * 21/135 = 3/20 * 21/5 = 63/100 6) (2 3/8 + 3 7/24) : (4 2/3 - 1 1/8) = (57/24 + 79/24) : (112/24 - 27/24) = 136/24 : 85/24 = 136/85 = 8/5 = 1 3/5 7) (3 1/4 + 2 1/3) : (7 1/2 - 1 2/3) = (39/12 + 28/12) : (45/6 - 10/6) = 67/12 : 35/6 = 67/12 * 6/35 = 67/70 8) (4 4/5 + 3 3/8 + 2 1/4) = 4 32/80 + 3 30/80 + 2 20/80 = 9 82/80 = 10 1/40 9) (3,6 - 1 1/3) : (4 1/15 - 2 7/9) = (18/5 - 4/3) : (61/15 - 25/9) = (54/15 - 20/15) : (183/45 - 125/45) = 34/15 : 58/45 = 34/15 * 45/58 = 17/1 * 3/29 = 51/29 = 1 22/29 10) 4 1/6 * (1 1/2 - 2/5) + (3/4 + 5/6) = 25/6 * (15/10 - 4/10) + (9/12 + 10/12) = 25/6 * 11/10 + 19/12 = 5/6 * 11/2 + 19/12 = 55/12 + 19/12 = 74/12 = 37/6 = 6 1/6