Bonjour,

308/2 =154

154/2 =77

77/7 =11

=> 2*2*7*11

252/2 =126

126/2 = 63

63*3 =21

21/3 =7

=> 2*2*3*3*7

1 470/2 =735

735/3 =245

245/5 =49

49/7 =7

=> 2*3*5*7*7

3 780/2 =1 890

1 890/2 =945

945/3 =315

315/3= 105

105/3 =35

35/5 =7

=> 2*2*3*3*5*7

c)

1)

ce sont 2 nombres pairs, ils ont 2 comme diviseur en commun

2)

396/2 =198

198/2 =99

99/3 =33

33/3 = 11

=> 2*2*3*3*11

378/2 =189

189/3 =63

63/3 =21

21/3 =7

=> 2*3*3*3*7

a)

2; 3 ; 6; 9; 18;

b)

2*3*3 = 18