A = 1/3 + 2/5 - 3
=5/15+6/15-45/15
=-34/45
B = 6 - 4 x (1/4 - 1)²
=6-4(1/4-4/4)²
=6-4(-3/4)²
=6-4x(9/16)
=6-36/16
=6-9/4
=24/4-9/4
=15/4
C = 5/14 + 3 x 1/42
=5/14+3/42
=5/14+1/14
=6/14
=3/7
D = 1 - 1/3 / 1/4 - 2
=(3/3-1/3) / (1/4-8/4)
=(2/3)/(-7/8)
=2/3 x (-8/7)
=-16/21
