Can you do absolute value in lua?

If you do print(|-3|) would it print 3? I tried this once and it didn't work, but I still think there is a way to find absolute value. I want it to be simple and not like:

local number = {-4, 4, 5, -98}

for _, num in pairs(number) do
	if num > 0 then
	num = num*-1
	print(num)
	else
	print(num)
end

I also want to know if you can do factorial in lua: print(3!) should print 6, unless I've done it wrong(that would be embarrassing.) This is how you could do it but it's too long.

local number = {3, 5, 7}

for _,num in pairs(number) do
	if num == 0 then
	print(1)
	elseif num < 0 then
	repeat
		bleh = -1
		num = num*num+bleh
		bleh = bleh-1
	until num-bleh = 1
	print(num)
	elseif num > 0 then
	repeat
		bleh = 1
		num = num*num-bleh
		bleh = bleh+1
	until num+bleh = -1
	print(num)
	end
	end
end

Thanks in advance! BTW: I know these scripts don't work, I made them in under a min. Expect bugs and me spelling things wrong.