AMPscript Add Function
https://gist.github.com/nmaratasdev/594f7d9d0e4c0bae6f279baaaae2cade
AMPscript Subtract Function
https://gist.github.com/nmaratasdev/06748b1bf9f20da79bc35df386b86277
AMPscript Multiply Function
https://gist.github.com/nmaratasdev/f28a32fdc9c2f8aba8ab5fe701d3fed2
AMPscript Divide Function
https://gist.github.com/nmaratasdev/eead756b805739dd7e8c48542da339ef
AMPscript Mod Function
https://gist.github.com/nmaratasdev/973bf87cd432dfd90ef003d6a7a8b99a