Bonsoir,
7/6 + 5/9 - 11/18
= 7 x 3 / 6 x 3 + 5 x 2 / 9 x 2 - 11/18
= 21/18 + 10/18 - 11/18
= 31/18 - 11/18
= 20/18
= 2 x 10 / 2 x 9
= 10/9
5/6 x 1/4 x 4/3
= 5/24 x 4/3
= 20/72
= 4 x 5 / 4 x 18
= 5/18
(6 - 6/5) x 5/3
= (6 x 5 / 1 x 5 - 6/5) x 5/3
= (30/5 - 6/5) x 5/3
= 24/5 x 5/3
= 120/15
= 15 x 8 / 15 x 1
= 8