1. Write these notes in your spirals!
Roman Numerals
Write these notes in your spirals!

2. Roman Numerals Are expressed by letters of the alphabet. I = 1 V = 5 I
C = 100
D = 500
M = 1000 I
Value
Xylophones
Like
Cows Do
Milk

3. Rules A letter repeats its value as many times as it appears
X = 10 XX= 20 XXX= 30
BUT…
Values can only repeat 3 times
The “fives” (V, L, D) do NOT repeat

4. THESE ARE THE ONLY “LEGAL” SUBTRACTION PAIRS!
Rules
If one or more letters are placed after letters of greater value, add the values together.
VI = 6 (5 +1)
MC = 1100 ( )
If a letter is placed before a letter of greater value, subtract that amount
IV = 4 (5-1) XL = 40 (50-10)
IX = 9 (10-1) XC = 90 (100-10)
CD = 400 ( ) CM=900 ( )
THESE ARE THE ONLY “LEGAL” SUBTRACTION PAIRS!

5. Rules
Except for the “legal” subtraction pairs, Roman numerals descend in value from left to right.
MMDCCLXVI = 2766 ( )
MCMXCIX = 1999 [1000+( )+( )+(10-1)]