A = 11/45 - (-5/9)
A = 11/45 + 25/45
A = 36/45
A = (9x4)/(9x5)
A = 4/5
B = 12/5 x (-10/9)
B = (3x4)/5 x (-2x5)/(3x3)
B = 4 x (-2)/3
B = (-8/3)
C = -21/28 : 4/9
C = (-3x7)/(4x7) x 9/4
C = (-3/4) x 9/4
C = (-27/16)
D = 5/9/(-8)
D = 5 x (-8)/9
D = (-40)/9
E = 56/5 : 7
E = 56/5 x 1/7
E = (8x7)/5 x 1/7
E = 8/5
F = 8/3-5/7/20 : 21
F = 8/3 - 5 x 20/7 x 1/21
F = 8/3 - 100/147
F = (49x8)/147 - 100/147
F = 392/147 - 100/147
F = 292/147
G = (2/5 : 8/15):4/7:5/21
G = (2/5 x 15/8)x7/4x21/5
G = 3/4 x 7/4 x 21/5
G = 441/80
H = 1/3-1:7/6-2
H = 1/3 - 1 x 6/7 - 2
H = 1/3 - 6/7 - 2
H = 7/21 - 18/21 - 42/21
H = -53/21