//To add in Java script, you have to put an additon symbol '+' between them. If you have stored two numbers in variables, just put an addition symbol between the variable names.
//For example:
var a = 5
var b = 6
var c = a+b
var d = 5+6

Bot.send (c)/ print (c)// or whatever you use to get output
Bot.send (d)/ print (d)// or whatever you use to get output

//output will be: 11, 11