how would I round to the nearest?

I am trying to make a function that will round a given value to the nearest given second number. I'll admit it, today my brain kinda broke. If anyone could give me a hand with some simple math, I would appreciate it.

function calcround(number,inc) 
	return math.floor(number/inc + (inc / .25)) * inc
end

print(calcround(31.75,1))