It's kinda simple I think.
Essentially, is this possible
local random = math.random(10,15)
-- use random later
hum.WalkSpeed = hum.WalkSpeed - random
That's first of all.
Second of all, will that variable stay as one assigned variable? Say, if math.random pulls out 14, will it stay as 14 when I do:
hum.WalkSpeed = hum.WalkSpeed - random
In addition, if this is in a function which only runs when it's hit, does random change again?
Thanks!

2 comments
You can make a function to return math.random(10,15) ie local random = function() return math.random(10,15) end
OK! Will try.