9/20 * 2/3 + 5/14 * 7/25 = 3/10 + 1/10 = 4/10 = 2/5
3 3/4 * 2/5 - 3 6/25 * 5/27 = 15/4 * 2/5 - 81/25 * 5/27 = 3/2 - 3/5 = 15/10 - 6/10 = 9/10
2 2/5 * 5/6 - 3/4 * 1 2/3 = 12/5 * 5/6 - 3/4 * 5/3 = 2 - 5/4 = 8/4 - 5/4 = 3/4
1 17/28 * 7/9 + 14/25 * 5/7 = 45/28 * 7/9 + 14/25 * 5/7 = 5/4 + 2/5 = 25/20 + 8/20 = 33/20 = 1 13/20