Bjr
A = 1/15+1/3-3/20
A = 4+20-9/60
A = 15/60
A = 1/4
B = 2/3×5/7
B = 2×5/3×7
B = 10/21
C = 1/3×5
C = 1/3×5/1
C = 1×5/3×1
C = 5/3
D = -4×-2/13
D = 8/13
E = 2/3/5/3
E = 2/5
F = 3/7/2
F = 3/7÷2
F = 3/7×1/2
F = 3×1/7×2
F = 3/14
G = -12/-49/-3/-35
G = 12/49/3/35
G = 20/7