900 in Roman Numerals

How to write 900 in Roman numerals

Roman numerals are built place by place, from the largest value to the smallest. For 900 the places are 900 (hundreds).

1. Write 900 as CM.

Joined together, CM gives CM.

900 digit by digit

Check CM by reading it back

Reading CM from left to right and adding the pieces: CM = 900. Together that is 900, so CM and 900 match.

Mistakes to avoid with CM

• Do not write the 4s and 9s additively. 900 uses subtractive pairs (CM for 900), not strings like IIII or VIIII.
• Only I, X and C may be placed before a larger symbol to subtract, so CM never contains forms such as VX or LC.
• Read CM as one number, not letter by letter: add the values left to right, except where a smaller symbol sits before a larger one.

Facts about the number 900

• 900 is an even number and composite, with prime factors 2² x 3² x 5².
• In binary 900 is 1110000100 and in hexadecimal it is 384.
• Written out, 900 is "nine hundred".
• The digits of 900 add up to 9, so it is divisible by 3.
• 900 is a perfect square (30 x 30).

Where you will see 900 in Roman numerals

The number 900, written as CM in Roman numerals, appears on older buildings or monuments to mark a construction year. It is carved this way because stone inscriptions traditionally use Roman letters for dates, lending a sense of permanence and formality.

Numbers near 900

More roman numerals

• 800 (DCCC): previous page
• 950 (CML): next page
• Roman numerals chart: the full list