A number is even if it is perfectly divisible by 2. When the number is divided by 2, we use the remainder operator `%`

to compute the remainder. If the remainder is not zero, the number is odd.

## Source Code

```
# Python program to check if the input number is odd or even.
# A number is even if division by 2 gives a remainder of 0.
# If the remainder is 1, it is an odd number.
num = int(input("Enter a number: "))
if (num % 2) == 0:
print("{0} is Even".format(num))
else:
print("{0} is Odd".format(num))
```

**Output 1**

Enter a number: 43 43 is Odd

**Output 2**

Enter a number: 18 18 is Even

In this program, we ask the user for the input and check if the number is odd or even.