bonjour
A = ( 2/3 - 9 /10 ) : ( 2 - 3 /5 )
A = ( 20/30 - 27/30 ) : ( 10/5 - 3 /5 )
A = - 7/30 : 7/5
A = - 7/30 x 5/7
A = - 35/210 = - 1/6
B = 4/5 + 6/5 : ( 32/45 x 27/48 - 2 /3 )
B = 4/5 + 6 /5 : (864/2160 - 2 /3 )
B = 4/5 + 6 /5 : ( 2/5 - 2/3)
B = 4/5 + 6 /5 : ( 6/15 - 10/15)
B = 4/5 + 6/5 : - 4 /15
B = 4/5 + 6/5 x - 15/4
B = 4/5 - 90/20
B = 16/20 - 90/20
B = - 74/20 = - 37/10
