Bonjour
A = 2 + [8 : (9 + 5/19)]]
A = 2 + [8 : [(9 x 19) / (1 x 19) + 5/19]]
A = 2 + [8 : (171/19 + 5/19)]
A = 2 + [8 : 176/19]
A = 2 + [8 x 19/179]
A = 2 + 152/179
A = (2 x 179) / (1 x 179) + 152/179
A = 358/179 + 152/179
A = 510/179
B = (1/8 + 3/4 - 1/12) : (5/6 + 1/3 + 2)
B = [(1 x 3) / (8 x 3) + (3 x 6) / (4 x 6) - (1 x 2) / (12 x 2)] : [5/6 + (1 x 2) / (3 x 2) + (2 x 6) / (1 x 6)]
B = (3/24 + 18/24 - 6/24) : (5/6 + 2/6 + 12/6)
B = 15/24 : 19/6
B = 15/24 x 6/19
B = 90/456
B = (6 x 15) / (6 x 76)
B = 15/76.