To solve this problem, we need to determine the value of x, which represents the sum of the digits in the year 2010.
The first year after 2010 in which the sum of the digits is 3 again is 2100.
Let's break down the information given:
Year 2010: sum of the digits = X$
Year 2100: sum of the digits = 3
We can set up the equation as follows:
Sum of digits in year 2010 = Sum of digits in year 2100
X = 3
Therefore, the value of the unknown variable x is 3.
The answer is: 3
Below is a math problem. Provide a detailed, step-by-step solution.

### Problem:
In 2010, the sum of the year's digits is X$. The first year after 2010 in which the sum of the digits is 3 again is 2100. What is the value of unknown variable X?

### Answer:
