Whole numbers are the set natural numbers including with zero. 0 is the smallest whole number. Whole numbers are 0, 1, 2, 3, etc. All-natural numbers are whole numbers, but all whole numbers are not natural numbers. Deals with the calculation of natural numbers along with usage of Zero (0). Practising and doing calculations with number zero is important. The chapter prepares the student for doing calculations with higher value numbers in future. It is especially important for doing calculation with higher value numbers which contains zero in it. The chapter contains lots of different methods for calculation with whole numbers, including zero (0).