The final calculations are done on a per packet basis for the simple fact that you can't purchase part of a packet of smokes or tobacco.

If:

• a = Grams not smoked per day
• b = Grams per packet
• c = Days smokefree
• d = Cost per packet

then:

Total money saved =
RoundUp((a / b) x c) x d

RoundUp rounds the number its given to the nearest whole number.