Bonjour
M = 4/9 + 11/72
M = (4 x 8) / (9 x 8) + 11/72
M = 32/72 + 11/72
M = 43/72
N = 8/15 - 1/3
N = 8/15 - (1 x 5) / (3 x 5)
N = 8/15 - 5/15
N = 3/15
N = (3 x 1) / (3 x 5)
N = 1/5
O = 8/7 + 9/35
O = (8 x 5) / (7 x 5) + 9/35
O = 40/35 + 9/35
O = 49/35
O = (7 x 7) / (7 x 5)
O = 7/5
P = 3 - 2/10
P = (3 x 10) / (1 x 10) - 2/10
P = 30/10 - 2/10
P = 28/10
P = (2 x 14) / (2 x 5)
P = 14/5
Q = 11/15 + 1/6
Q = (11 x 2) / (15 x 2) + (1 x 5) / (6 x 5)
Q = 22/30 + 5/30
Q = 27/30
Q = (3 x 9) / (3 x 10)
Q = 9/10
R = 3/4 - 7/10
R = (3 x 5) / (4 x 5) - (7 x 2) / (10 x 2)
R = 15/20 - 14/20
R = 1/20.