Bonjour
A = (4/3 - 2/9) x 5/4
A = [(4 x 3)/(3 x 3) - 2/9] x 5/4
A = (12/9 - 2/9) x 5/4
A = 10/9 x 5/4
A = (10 x 5)/(9 x 4)
A = (2 x 5 x 5)/(9 x 2 x 2)
A = 25/18
B = 7/15 - 3/25 : 9/25
B = 7/15 - 3/25 x 25/9
B = 7/15 - (3 x 25)/(25 x 9)
B = 7/15 - 3/9
B = 7/15 - 3/(3 x 3)
B = 7/15 - 1/3
B = 7/15 - (1 x 5)/(3 x 5)
B = 7/15 - 5/15
B = 2/15
C = (5/6 - 2/9) x 7/11
C = [(5 x 3)/(6 x 3) - (2 x 2)/(9 x 2)] x 7/11
C = (15/18 - 4/18) x 7/11
C = 11/18 x 7/11
C = (11 x 7)/(18 x 11)
C = 7/18
