Find the number of three-digit numbers from 100 to 999 including all numbers which have any one digit that is the average of the other two.

Explanation

To find the number of three-digit numbers from 100 to 999 that have any one digit as the average of the other two, we can follow these steps:

### Step 1: Understand the condition
We need to find three-digit numbers represented as \(abc\) (where \(a\), \(b\), and \(c\) are the digits). The condition states that one of the digits must be the average of the other two. This can be expressed mathematically as:
- \(a = \frac{b + c}{2}\)
- \(b = \frac{a + c}{2}\)
- \(c = \frac{a + b}{2}\)

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