827.
1) 1 / (4/5) = 1 * 5/4 = 5/4 = 1 1/4,
2) 1 / (1/2) = 1 * 2 = 2,
3) 1 / (5 2/3) = 1 / (17/3) = 1 * 3/17 = 3/17,
4) 1 / (7/8) = 1 * 8/7 = 8/7 = 1 1/7,
5) 1 / (9/10) = 1 * 10/9 = 10/9 = 1 1/9,
6) 1 / (8/11) = 1 * 11/8 = 11/8 = 1 3/8,
829.
1) (1 2/3) / (2 1/2) = (5/3) / (5/2) = 5/3 * 2/5 = 2/3,
2) 12 / (1 1/5) = 12 / (6/5) = 12 * 5/6 = 2 * 5 = 10,
3) (3 3/4) / (1 1/4) = (15/4) / (5/4) = 15/4 * 4/5 = 15/5 = 3,
4) (11 1/4) / (4 1/2) = (45/4) / (9/2) = 45/4 * 2/9 = 5/2 = 2 1/2,
5) (5 1/4) / (1 3/4) = (21/4) / (7/4) = 21/4 * 4/7 = 21/7 = 3,
6) (3 1/8) / (1 1/4) = (25/8) / (5/4) = 25/8 * 4/5 = 5/2 = 2 1/2,
830.
1) (5/8 * 2/3) / (5/9) = 5/12 * 9/5 = 9/12 = 3/4,
2) (3/4 * 1/3) / (1/2) = 1/4 * 2 = 1/2,
3) (7/15 * 3 3/4) / (2 5/8) = (7/15*15/4) / (21/8) = 7/4 * 8/21 = 2/3,
4) (5/12 * 4/5) / (2/9) = 1/3 * 9/2 = 3/2 = 1 1/2