Last updated on May 26th, 2025
Roman numerals are a way of expressing numbers using symbols. I, V, X, L, C, D, and M are the symbols we use. Roman numerals are used in royal titles, book names, sequences, and so on. Here we will be discussing Roman numerals, rules, and examples.
The royal titles, such as Henry I, Henry II, and so on, have symbols that represent Roman numerals. Earlier people used to count using fingers, sticks, bones, etc. As life became complex, a standard form was required to count.
Ancient Romans used the Roman numeral system to count. I (1), V (5), X (10), L (50), C (100), D (500), and M (1000) are the symbols we use to count. In Roman numerals, we use DCXC to represent 690, where D is 500, C is 100, X is 10.
Let’s learn more about Roman numerals and how we write them.
There are certain basic rules to write a number in Roman numerals. In this section, let’s discuss some basic rules that need to be remembered when writing a number in Roman numerals.
The addition method is used when a smaller number is placed after a larger number. For example, DCXC → D + C + X + C → 500 + 100 + 10 + 100 = 690
To write a large number, some Roman numerals can be repeated up to three times. For example, CCC → 300.
If a small number is followed by a larger number in Roman numerals, we subtract the smaller number from the larger number. For example, XC → C - X → 100 - 10 = 90
The symbols cannot be repeated more than three times, and some symbols like V, L, and D cannot be repeated. For example, we won't write DD for 1000 instead we use M.
Let’s now learn how to write 690 in Roman numerals. Follow these methods to write the number in Roman numerals.
In the expansion method, based on the place value, the number is broken down. In this section, we will learn how to write 690 in Roman numerals using the expansion method. To write 690 in Roman numerals, follow the steps:
Step 1: The number is broken down based on place value. Place value includes ones, tens, hundreds, etc. For 690, we write it as 500 + 100 + 90
Step 2: Converting the number into Roman numerals
Step 3: Combining the Roman numerals together. Therefore, 690 in Roman numerals is D (500) + C (100) + XC (90) = DCXC
When writing a large number into Roman numerals, we group the number. To write 690 in Roman numerals, we group 690 as 500 + 100 + 90
So, 690 is written as DCXC in Roman numerals.
Students often make mistakes when writing a number in Roman numerals. To master Roman numerals, we can learn a few common mistakes and the ways to avoid them.
A historian is studying the ancient Roman census records and finds a document listing DCCCLX people in one region and CLXX in another. What is the difference in population between these two regions?
The difference in population between the two regions is DCXC.
To find the difference, subtract the smaller number from the larger one.
DCCCLX = 860
CLXX = 170
860 - 170 = 690
690 in Roman Numerals is DCXC.
An archaeologist uncovers a map showing an ancient Roman road stretching for DCCC miles, but a section of DCX miles has been lost to erosion. How many miles of the road remain intact?
The intact miles of the road are CLXXX.
To find the remaining miles, subtract the eroded section from the total.
DCCC = 800
DCX = 610
800 - 610 = 190
190 in Roman Numerals is CLXXX.
A collector has a total of MCMLXXX coins, out of which he wants to donate DCXC to a museum. How many coins will he have left after the donation?
The number of coins left after the donation is MCCXC.
Subtract the number of donated coins from the total.
MCMLXXX = 1980
DCXC = 690
1980 - 690 = 1290
1290 in Roman Numerals is MCCXC.
A Roman architect designed a building that initially required DCCCXL bricks, but they revised the plan to need DCXC bricks less. How many bricks are now needed for the building?
The total number of bricks now needed is CL.
Subtract the revised amount from the original number of bricks.
DCCCXL = 840
DCXC = 690
840 - 690 = 150
150 in Roman Numerals is CL.
Write the Roman Numeral for 500 + 190 using the expansion method.
The Roman numeral for 500 + 190 is DCXC.
Step 1: Convert the numbers 500 and 190 into Roman numerals.
500 - D
190 - CXC
Step 2: Add the numbers together: 500 + 190 = 690
Using the expansion method: 690 = 500 + 100 + 90 = DCXC
Hiralee Lalitkumar Makwana has almost two years of teaching experience. She is a number ninja as she loves numbers. Her interest in numbers can be seen in the way she cracks math puzzles and hidden patterns.
: She loves to read number jokes and games.