A = 15/21 * 14/25 = 3/3 * 2/5 = 2/5
B = 8/3 * (-9)/6 = 8/3 * (-3)/2 = 4/1 * (-1)/1 = -4
C = 60/7 * 21/(-4) = 15/1 * 3/(-1) = - 45
D = 7/1 * 4/(-21) = 1/1 * 4/(-3) = -4/3
E = 11/1 * 15/(-22) = 1/1 * 15/(-2) = -15/22
F = 56/5 * 1/(-7) = 8/5 * 1/(-1) = -8/5
