1. What is the difference between natural numbers and whole numbers?

Whole numbers include zero.

2. What are irrational numbers?

Irrational numbers are any numbers that cannot be written as a fraction. e.g. Numbers that never end on the calculator and have no pattern, such as 3.1415923565...

3. What is the biggest multiple of 9?

There is never a biggest ever multiple. Multiples form INFINITE sets that go on and on and on and on and ...

4. Is "1" a prime number?

No, "1" is a special number but it is not classed as a prime number.

5. Is "2" a prime number?

Yes, because 2 has only two factors i.e. 2 and 1, it is classed as a prime number.

6. What is the reciprocal of 0?

The reciprocal of zero is not defined because you cannot say how many times zero divides into anything.

7. Can any number be written in standard form?

Yes, any number however small or large can be written in standard form.