I was supposed to get a 100 calorie pack but had to eat half the bag of pretzels which is around 20 - 30 calories more . It's hard to be sure the exact number of calories so i'm a little bothered . I know the bag is 220 but i only had half so i m guessing 110 - 130 . 
Question: Why was I supposed to get a 100 calorie pack ?
Because I'm trying to lose weight .