Fill in the blanks.
(i) The product of any two whole numbers is a _______ number.
(ii) If a and b are any two whole numbers and b < a, then a – b is a _______ number.
(iii) The product of a whole number and zero is _______.
(iv) The product of a whole number and one is _______.
| (i) | (ii) | (iii) | (iv) | |
| A | Whole | Integer | 1 | 1 |
| B | Natural | Whole | 1 | 1 |
| C | Whole | Whole | 0 | the number itself |
| D | Natural | Integer | 0 | the number itself |