Can you guess what 4 is?

You may think it's 4 I's, but it's actually:

IV = 4

What is that **V **symbol?

In Roman numerals, **V **is the symbol for 5.

V = 5

In Roman numerals, you never write more than 3 of the same symbol in a row.

That's why after III comes IV.

So, what do you think comes after V?

We add another I.

VI = 6

We can add one more **I** to get 7.

VII = 7

In Roman numerals, it's ok to have 3 of any symbol in a row, but no more. So after 7 comes:

VIII = 8

Now what do we do? We can't add another I. So we need to use a new bigger symbol:

X = 10

To make 9, we take away 1 from 10:

IX = 9

**Remember:** when we write **I** **before **a bigger symbol like V or X, we take away from that number.

Great job learning to count from I to X in Roman numerals.

To count to 10, you've had to use 3 of the symbols that make up Roman numerals: **I,** **V,** **X.**

Now let's learn the other 4 symbols: **L,** **C,** **D, **and **M.**

### Roman Numerals L, C, D, M

Roman numerals are all made up of **seven ****symbols.**

You just learned I, V, and X. Here are the 4 bigger symbols:

L= 50

C= 100

**Tip:** a **c**entury** **is 100 years. It starts with c.

D= 500

M= 1,000

**Tip:** a **m**illennium** **is 1,000 years! It starts with m.

**TIP!**

You can **use** **this** **sentence **to help you remember the order:

### Rules for Roman Numerals

All Roman numerals are **combinations **of the basic 7 symbols.

These combinations follow **four** **important** **rules:**

**Rule** **1:**** **When a smaller symbol is **after** a greater symbol, it's **added.**

For example,

VI=5+1=6

**Rule** **2:** If a symbol comes after itself, it's added.

XX=10+10=20

CCLX=100+100+50+10=260

**Rule** **3: **When a smaller symbol appears **before **a greater symbol, it is **subtracted.**

For example,

IX=10-1=9

XL=50-10=40

CM=1000-100=900

**Rule** **4: **The same symbol **cannot** **be** **used** **more** **than** **three** **times **in a row.

For example,

XXX=10+10+10=30,but40is notXXXX.

CCC=100+100+100=300,but400is notCCCC.

### Roman Numerals: Basic Numbers

Let's now use these rules to learn some basic Roman numerals.

1 =I

2 =1+1=II

3 =1+1+1=III

4 =5-1=IV

5 =V

6 =5+1=VI

7 =5+1+1=VII

8 =5+1+1+1=VIII

9 =10-1=IX

10 =X

20 =10+10=XX

30 =10+10+10=XXX

40 =50-10=XL

50 =L

60 =50+10=LX

70 =50+10+10=LXX

80 =50+10+10+10=LXXX

90 =100-10=XC

100 =C

200 =100+100=CC

300 =100+100+100=CCC

400 =500-100=CD

500 =D

600 =500+100=DC

700 =500+100+100=DCC

800 =500+100+100+100=DCCC

900 =1000-100=CM

1000 =M

Great work! 👏

### Converting Roman Numerals to Digits

Look at this Roman numeral.

CDLXIV

**To** **convert** **a** **Roman** **numeral** **into** **digits,** find the value of each symbol in it, and then add or subtract these values.

Let's try to do that now!

First, let's **find** **the** **value **of each symbol.

Now, let's see if there are any **smaller** **symbols** **appearing** **before** **bigger** **symbols.**

This is because we need to **subtract **those values (**Rule** **3**)!

Here is **Rule 3 **one more time:

Rule3:When a smaller symbol appears before a greater symbol, it is subtracted.

Now, let's add/subtract the values.

CDLXIV= (500-100) + (50+10) + (5-1)

=400 +60 +4

So, what's the value of this Roman numeral?

Yes:

CDLXIV= 464

Awesome!

Let's try one more example.

MDCXLI

How can we turn this into a number?

First, we **find** **the** **values **of all the symbols.

Next, we find any smaller symbols that appear before bigger symbols.

Finally, we add or subtract the values.

MDCXLI=1000+500+100+ (50-10) +1

= 1000 + 600 + 40 + 1

So, the value of this Roman numeral is:

MDCXLI= 1,641

Perfect.

### Converting Digits to Roman Numerals

Now, let's try converting this number into a Roman numeral.

2,342

**To** **convert** **a** **number** **into** **a** **Roman numeral,** break the number into thousands, hundreds, tens, and ones. Then write the letters for each value.

Let's try it.

2,342 =2000 +300 +40 +2

So, what is the answer?

2,342 =MMCCCXLII

Nice job! 👏

Let's try one last example.

Convert this number into a Roman numeral.

978

Let's do it!

978 =900 +70 +8

So, what's the answer?

978 =CMLXXXVIII

You did great learning about Roman numerals. 👏

Try the practice to see if you got it.