Whole Numbers are the numbers that contain all positive numbers and 0. All mathematical operators addition, subtraction, multiplication, exponents and Square-root can be processed on it. Every Whole Number has a successor and every whole number has a predecessor, which means that one can be added to every whole number and one can be subtracted from every whole number except 0.
If we subtract 1 from 0, we get -1 as the result, which is not a whole number but a negative Integer. Subtracting whole numbers is as simple as doing backward counting. Suppose we need to subtract 4 from 23, we simply count backward 4 steps and get 22, 21, 20, 19. It gives us 19 as the result. Now this can also be done by moving towards left direction certain number of steps on the number line. If we are on 23 and we move 4 steps towards left in the number line, we get 19. So 19 is the answer.
Also we must remember when 0 is subtracted from any whole number, the result remains unchanged. While doing whole number subtraction for larger number, we need to put the larger number up and the smaller number under it. Subtraction of whole numbers can be explained by an example: