300 in Roman numerals

300 in Roman numerals is CCC.

Pick any whole number from 1 to 3,999.

300 = \text{CCC}

How to work it out

1
Take the biggest Roman value that fits, write its letter, subtract it, and repeat.
2
Here: 100 (C) + 100 (C) + 100 (C) = 300.
3
Joined together: CCC. (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.)

What is 300 in Roman numerals?

CCC.

How do you read CCC?

CCC = 100 + 100 + 100 = 300.