Bonjour, j’ai du mal à résoudre mes calcul voudrai bien m’aider merci d’avance

Ex1

A=-13/8+7/16

=(-26+7)/16

=-19/16

B=7/35+8/15

=((7÷7)/(35÷7))+8/15

=1/5+8/15

=(3+8)/15

=11/15

Ex2

H=63/30×45/28

=((63÷3)/(30÷3))×45/28

=21/10×45/28

=945/280

=(945÷35)/(280÷35)

=27/8

J=24/35÷36/14

=24/35÷((36÷2)/(14÷2))

=24/35÷18/7

=24/35×7/18

=168/630

=(168÷42)/(630÷42)

=4/15

Ex3

M=-14/15+10/15×7/20

=-14/15+((10÷5)/(15÷5))×7/20

=-14/15+2/3×7/20

=-14/15+14/60

=-14/15+((14÷2)/(60÷2)

=-14/15+7/30

=(-28+7)/30

=-21/30

=-(21÷3)/(30÷3)

=-7/10

J=(1/8-7/12)÷(7/6+7/16)

=((12-56)/96)÷((112+42)/96)

=(-44/96)÷154/96

=-((44÷4)/(96÷4))÷/((154÷2)/(96÷2))

=-11/24÷77/48

=-11/24×48/77

=-528/1848

=-(528÷264)/(1848÷264)

=-2/7