A = 1/12 + 3/12
A = 4/12
A = 4 x 1 / 4 x 3
A = 1/3
B = 19/7 - 5/7
B = 14/7
B = 7 x 2 / 7 x 1
B = 2/1
B = 2
C = 1/2 + 7/8
C = 1 x 4 / 2 x 4 + 7/8
C = 4/8 + 7/8
C = 11/8
D = 3 + 1/5
D = 3 x 5 / 1 x 5 + 1/5
D = 15/5 + 1/5
D = 16/5
E = 7/2 - 3/4
E = 7 x 2 / 2 x 2 - 3/4
E = 14/4 - 3/4
E = 11/4
F = 3/5 + 7/10 - 1
F = 3 x 2 / 5 x 2 + 7/10 - 1 x 10 / 1 x 10
F = 6/10 + 7/10 - 10/10
F = 13/10 - 10/10
F = 3/10