501 in Roman numerals

501 in Roman numerals is DI.

Pick any whole number from 1 to 3,999.

501 = \text{DI}

How to work it out

1
Take the biggest Roman value that fits, write its letter, subtract it, and repeat.
2
Here: 500 (D) + 1 (I) = 501.
3
Joined together: DI. (Four of the same letter in a row is never used: 4 is IV, 9 is IX, 40 is XL, 90 is XC, 400 is CD, 900 is CM.)

Value	Letters
500	D
1	I

What is 501 in Roman numerals?

DI.

How do you read DI?

DI = 500 + 1 = 501.