How to do arthimetic operations on database values in django

[Mohan Goud]

I have Prof:AssociateProf:AssistantProf = x:y:z in database and I have to do these operations x/(x+y+z) : y/(x+y+z) : z/(x+y+z) in django. Can anyone help me on this and models.py is

class Show(models.Model) :
Total = models.IntegerField(default = 0)
Prof = models.IntegerField(default = 0)
AssociateProf = models.IntegerField(default = 0)
AssistantProf = models.IntegerField(default = 0)
ResearchScholar = models.IntegerField(default = 0)
MTech = models.IntegerField(default = 0)