Can you update a number variable based on number shown in text box?

I’m trying to build a prototype where a number will change based on some randomization. The idea is I have my Total number variable, and my Modifier number variable which are added together to update the Total. I’d love for the Modifier number variable to pull randomly from a list. It seems the best way to do this is to use a randomizer plugin that updates a text field from a list, but then I can’t figure out how to get the Modifier variable in my variable settings to use that number. Also open to totally different ways to solve / try this if it gets to the same result of having a base value that can be randomized within certain parameters. Thanks so much!