To find the total number of servings Jeremy can make from the value pack, we need to divide the total number of ounces in the value pack by the weight of each serving.
The value pack contains 42 1/2 cheese crackers, which can be written as 42.5.
Each serving weighs 1 1/4 ounces, which can be written as 1.25.
Therefore, the total number of servings Jeremy can make is:
42.5 / 1.25 = 34 servings. Answer: \boxed{34}.