Even and Odd Numbers

Basically Numbers can be classified into 2 types.
1. Even Numbers
2. Odd Numbers

Even Numbers:
These are the numbers which can be divisible by 2 or multiples of 2.
Ex: 0, 2, 4, etc.

Odd Numbers:
These are the numbers which are not divisible by 2 or not multiples of 2.
Ex: 1, 3, 5, etc.

Operations on Even and Odd numbers:
Addition
even + even = even
Ex: 2 + 2 = 4
odd + odd = even
Ex: 3+3 = 6
even + odd = odd
Ex: 2 + 3 = 5

Subtraction
even - even = even
Ex: 4-2=2
odd - odd = even
Ex: 3-1 = 2
even - odd = odd
Ex: 2 -1 = 1
odd - even = odd
Ex: 3-2 = 1

Multiplication
even * even = even
Ex: 4* 2=8
odd * odd = odd
Ex: 3* 5=15
even * odd = even
Ex: 4* 1=4

Powers/Exponents
even ^ even = even
Ex: 2 ^2 = 4
odd ^ odd = odd
Ex: 3^3= 9
even ^ odd = even
Ex: 2 ^3= 8
odd ^ even = odd
Ex: 3^2 = 9

Factorials
even! = even
Ex: 4! = 24
odd! = even (except 1!)
Ex: 3! = 6

Points to be remembered
1. Least non-negative even number: 0
2. Least positive even number: 2
3. Least non-negative odd number: 1
4. 0 * non-zero number = 0
5. 0 * 0 = not defined
6. 0/non-zero number = 0
7. non-zero number/0 = infinte
8. 0 / 0 = not defined (not infinite)
9. non-zero number ^ 0 = 1
10. 0 ^ 0 = not defined
11. 1 ^ infinite = not defined
12. (any number other than 0, 1) ^ infinite = infinite
Ex: 2^infinite = infinite
13. 0! = 1
14. Factorial of any odd no. except 1! is even because of the presence of 2.