400 in Roman Numerals

The royal titles, such as Henry I, Henry II, and so on, use Roman Numerals. Have you noticed these names and wondered what the symbols (I and II) represented? Those are Roman Numerals. In earlier times, people used fingers, sticks, and bones to count. As life became complex, a standard form was required, and the ancient Romans developed the Roman Numeral system. The symbols I (1), V (5), X (10), L (50), C (100), D (500), and M (1000) are used.

In Roman Numerals, we use CD to represent 400. Here, C is 100, and D is 500. Let’s learn more about Roman numerals and how we write them.

There are certain basic rules for writing numbers in Roman Numerals. Let's discuss these rules that need to be remembered when writing numbers.

Rule 1: Addition Method

The addition method is used when a smaller number is placed after a larger number. For example, VI → V + I → 5 + 1 = 6.

Rule 2: Repetition Method

Certain Roman Numerals can be repeated up to three times. For example, CCC → 300.

Rule 3: Subtraction Method

If a smaller number precedes a larger number, we subtract the smaller number from the larger number. For example, XC → C - X → 100 - 10 = 90.

Rule 4: Limitation Rule

Symbols cannot be repeated more than three times, and some symbols like V, L, and D cannot be repeated. For example, we use XL for 40 instead of XXXX.

Let’s now learn how to write 400 in Roman Numerals. Follow these methods to write the number in Roman Numerals.

• By Expansion Method  

• By Grouping Method

In the expansion method, based on place value, the number is broken down. In this section, we will learn how to write 400 in Roman numerals using the expansion method.

To write 400 in Roman Numerals, follow these steps:

Step 1: Break the number based on place value. Place values are ones, tens, hundreds, etc.

For 400, we write it as 500 - 100

 
Step 2: Convert the numbers into Roman Numerals  

500 in Roman Numeral — D  

100 in Roman Numeral — C

 
Step 3: Apply the subtraction method.  

Therefore, 400 in Roman Numeral is D (500) - C (100) = CD  

When writing a large number in Roman Numerals, group the numbers.  

To write 400 in Roman Numerals, we group 400 as 500 - 100.  

500 in Roman Numeral — D  

100 in Roman Numeral — C  

So, 400 is written as CD in Roman Numerals.  

Roman Numerals follow a certain pattern. In this section, we will learn some numbers related to the Roman numeral 400.

CD = 400  
CDI = 401  
CDII = 402  
CDIII = 403  
CDIV = 404  
CDV = 405  
CDVI = 406  
CDVII = 407  
CDVIII = 408  
CDIX = 409  
 

• Addition rule: Used when a large number is followed by a smaller numeral, and the values are added. For example, VI = V + I = 5 + 1 = 6.

• Subtraction rule: Used when a smaller numeral precedes a larger one, and the smaller is subtracted from the larger. For example, CD = D - C = 500 - 100 = 400.

• Grouping method: Group numbers based on their place value and convert each group into Roman numerals. For example, 400 = 500 - 100 = CD.

• Repetition rule: Certain symbols (I, X, C, M) can be repeated up to three times. For example, CCC = 300.

• Limitation rule: Symbols like V, L, and D cannot be repeated. For instance, XL is used for 40 instead of XXXX.