Adding values to NumberRange

Alright so I’ll be straight, I’m trying to extend the Speed and Lifetime of a particle emitter by using the + operator. However, it’s not possible or at least this is what I’m guessing, as I keep getting the same error, aka “Attempt to perform arithmetic (add) on NumberRange”.
Yeah, I’ve looked on both the forum and google and I found nothing about this specific problem.
I tried with all of these: normal numbers (int), NumberRange.new(v1,v2), Vector2.new(v1,v2), but none of them work. For who’s wondering, I need to use the plus operator cause each ParticleEmitter has a different Speed and Lifetime, so just doing PartEmitt.Speed = NumberRange.new(15,15) will not look good.
If anyone knows if it is possible and, in this case, how to do this then it’d really help me out cause I’m both confused and annoyed.

What do you mean that this does not look good?

As I stated, each ParticleEmitter that I’ve made, have a different Speed and Lifetime, so giving them the same values will make them look repetitive and that’s not what I’m looking for. For example, a ParticleEmitter has 10 in Speed and 0.4 in lifetime and another one 20 and 0.7. Now, the boost would be of 5 and 0.2 but if I give them the same values, they will look too similar and “weird”, while if I use a + to add values (instead of setting them), they will look better cause if one has 10 and I add 5, it will be 15 while if another one has 20 in speed then it will be 25 and not 15 like the other one. It’s pretty confusing but yeah this is the thing.

as far as i know a numberrange is an array