There are two different components for doing arithmetic on data collections, @AbrahamYezioro .
The LB Arithmetic Operation component is for the case that you want to sum/subtract/multiply/divide one data collection by another (or a data collection by some number). Conversely, the LB Mass Arithmetic Operation is for cases where you want to sum a list of data collections together (or multiply them together, etc.). The latter component should give you what you need and is what I am recommending here.