Let’s break down the Roman numeral “DCXVII” into its constituent parts and convert it to a number:

- D represents 500.
- C represents 100.
- X represents 10.
- VII represents 5 + 1 + 1, which is 7.

Now, let’s add these values together:

500 (D) + 100 (C) + 10 (X) + 7 (VII) = 517

So, “DCXVII” in Roman numerals is equivalent to the number 517.

If you want to learn how to convert a whole number to Roman numerals, here are some basic rules:

- Start with the largest Roman numeral that is less than or equal to the number.
- Write down that Roman numeral.
- Subtract its value from the number.
- Repeat the process with the remainder until you have accounted for the entire number.

For example, to convert 517 to Roman numerals:

- Start with the largest Roman numeral less than or equal to 517, which is 500 (D).
- Write down “D.”
- Subtract 500 from 517, leaving us with 17.
- Now, the largest Roman numeral less than or equal to 17 is 10 (X).
- Write down “X.”
- Subtract 10 from 17, leaving us with 7.
- The largest Roman numeral less than or equal to 7 is 5 (V).
- Write down “V.”
- Subtract 5 from 7, leaving us with 2.
- Finally, the largest Roman numeral less than or equal to 2 is 1 (I).
- Write down “II” (two “I” numerals).

Combine these Roman numerals: D + X + V + II = DCXVII, which is 517.

That’s how you convert a whole number to Roman numerals.