A = 5/13 + 5/7 + -20/41 + 8/13 + -21/41
= (5/13 + 8/13) + [(-20/41) + (-21/41)] + 5/7
= 1 + (-1) + 5/7
=5/7
B = 5/7 . 2/11 + 5/7 . 12/11 + 5/7 . 7/11
= 5/7 . ( 2/11 + 12/11 + 7/11)
= 5/7 . 21/11
= 15/11
G = (-2)/3 + (-5)/7 + 2/3 + (-2)/7
= [(-2)/3 + 2/3] + [(-5)/7 + (-2)/7]
= 0 + (-1)
= -1
H = (-5)/7 . 2/11 + (-5)/7 . 9/11
= (-5)/7 . (2/11+9/11)
= (-5)/7 . 1
= (-5)/7
N = -5/13 + 5/7 + 20/41 + -8/13 + 21/41
= [(-5/13) + (-8/13)] + (20/41 + 21/41) + 5/7
= -1 + 1 + + 5/7
= 5/7
E = 5/7 . 12/11 + 5/7 . 12/11 + 5/7 . 17/11
= 5/7 . ( 12/11 + 12/11 - 17/11)
= 5/7 . 7/11
= 5/11
