recopie et complété a 3min= s b 4h= min c 3jours= h d 2h= s e 7,5 h= min f 3,25min= s

3 min = 3 x 60 secondes = 180 secondes
4 h = 4 x 60 minutes = 240 minutes
3 jours = 3 x 24 heures = 72 heures
2 h = 2 x 60 x 60 = 2 x 3 600 = 7 200 secondes
7,5 h = 7,5 x 60 = 450 minutes
3,25 min = 3,25 x 60 = 195 secondes