The average of first 10 odd numbers is _______.

The first 10 odd natural numbers are 1, 3, 5, 7, 9, 11, 13, 15, 17, and 19.
The sum of the first $n$ odd natural numbers is given by the formula:

$$\text{Sum}=n^2$$

For $n=10$:

$$\text{Sum}=10^2=100$$

The average is calculated as:

$$\text{Average}=\frac{\text{Sum}}{n}=\frac{100}{10}=10$$

Alternatively, the property states that the average of the first $n$ odd numbers is always equal to $n$. Therefore, for $n=10$, the average is 10.