math.Round rounds to the nearest integer.
math.Truncate rounds towards zero.
I needed it for some equations and thought I'd make a pull request for others.
This is practically the same function as math.Round, except it doesn't add 0.5, which makes it not rounds to the nearest integer.
local num = 54.59874
print( math.Truncate( num, 2 ) ) -- 54.59
print( math.Round( num, 2 ) ) -- 54.6