Solution - Roman numeral to integer

Read left to right.
If a smaller symbol comes before a larger one, treat them as one subtractive pair (for example, IX = 9).
Otherwise, each symbol stands alone.

For this input we get:

$$M\left(1000\right)+D\left(500\right)+C\left(100\right)+L\left(50\right)+X\left(10\right)+X\left(10\right)+X\left(10\right)+IX\left(9\right)$$