Bonjour
M = (1/5 - 3/10) : (1/6 - 1/2)
M = [(1 x 2) / (5 x 2) - 3/10] : [1/6 - (1 x 3) / (2 x 3)]
M = (2/10 - 3/10) : (1/6 - 3/6)
M = - 1/10 : (- 2/6)
M = - 1/10 x (- 6/2)
M = 6/20
M = (2 x 3) / (2 x 10)
M = 3/10.
