Bonjour;
A)
5/9 *5/5 +2/5 *9/9
= 25/45 +18/45
= 43/45
B)
1/6 *2/2 - 2/3 *4/4
= 2/12- 8/12
= -6/12
= -1/2
C)
-17/35 *15/15 -7/15*35/35
= -255/525 - 245/525
= -500/525
= -100/105
= -20/21
D)
3/4*3/3 -7/12 +5/18
= 9/12-7/12+5/18
= 2/12 +5/18
= 1/6 +5/18
= 1/6 *3/3 +5/18
= 3/18 +5/18
= 8/18
= 4/9