Lua does not know the difference between a whole number and a decimal. All numbers are simply real numbers. Sometimes, especially when working with grids, you might need only whole numbers. If that is the case, Lua has a built-in function to round down, math.floor, or to round up, math.ceil. This is how they can be used:
pi = 3.1415
three = math.floor(3.1415)
five = math.ceil(4.145)
print (pi) -- will print: 3.1415
print (three) -- will print: 3
print (five) -- will print: 5
Using functions might look foreign right now, but don't worry, they will be covered in detail later in the chapter.
Basic arithmetic operations such as adding, subtracting, multiplying, or dividing can be performed on integers. We will cover arithmetic operations in detail later on in the chapter, but for now, let's take a look at something simple, adding two numbers:
five = 3 + 2
print (five) -- will print 5
print (2 + 2) -- will print 4
print (five + 1) -- will print 6