The best way to do this is to find how many pretzels are in a one ounce bag, and then multiply this by the answer that you're looking for. In this case, you have to divide 64 by 16, giving you 4. Therefore, there are 4 pretzels in one ounce. Yu then have to multiply 4 by 5, giving ou 20. Therefore, in a five ounce bag of pretzels, there are 20 pretzels