eq: how do you read and write roman numerals? where do you see roman numerals? super bowl &...

EQ: How do you read and write Roman Numerals?

Where do you see Roman Numerals?

• Super Bowl & Olympics

• Movies

• Clocks

• Outlines

• Books

• Names (Henry VIII)

• Roman numerals are part of the ancient Roman number system that remains in use today. The history of Roman numerals dates back to 1st millennium BC when they were used to record numbers in stone, art and coins.

• Roman numerals add a classic style that Arabic numerals cannot. Arabic (decimal) numbers ( 0 to 9 ) were introduced into Europe about 900 AD and were adopted quickly for their convenience and mathematical ease of use.

Let’s Learn the Roman Numerals…

• I = one

• V = five

• X = ten

• L = fifty

• C = 100

• D = 500

• M = 1,000

There isn’t a symbol for zero.

The Rules for Writing Roman Numerals

• The letters should be arranged from largest to smallest.– 1510 is written MDX, largest to smallest

• Only powers of ten can be repeated. • Don’t repeat a letter more than three times in a

row.– 100 is written C, not XXXXXXXXXX (too many

repeats)

Rules Continued

• Numbers can be written using subtraction. • If you place any smaller number in front of a

larger number it symbolizes subtraction. • For example, IV=4. It is really saying that 5 - 1

equals 4.– Only powers for ten (I, X, C) can be subtracted.

– I can only be subtracted from V or X

Practice

• 515 = ?• 39 = ?

• 1005 = ?• 32 = ?• 9= ?

Answers

• 515 = DXV

• 39 = XXXIX

• 1005 = MV

• 32 = XXXII

• 9= IX

Adding Roman Numerals

• Write down the two numbers you are adding right next to each other

• Rearrange the letters so they start with the largest and end with the smallest.

• Then start combining similar letters.• Check you answer by adding the Arabic numbers.

Now Let’s Try Adding

Problem1. 23 + 58

Answer to the Adding Problem

Step 1. 23 + 58

Step 2. XXIII + LVIII

Step 3. XXIIILVIII

Step 4. LXXVIIIIII

Step 4. IIIIII = VI

Step 5. LXXVVI

Step 6. VV = X

Step 7. LXXXI = 81

Step 8. 23 + 58 = 81

Roman Numeral Number

I 1

V 5

X 10

L 50

C 100

D 500

M 1000

REALLY BIG NUMBERS!

If there is a line under the Roman Numeral “V, X, L, C, D, or M” it means to add 3 zeros (multiply it by 1,000).

V would mean 5,000.

VIV

IXLII

Now try these:

1. XXXVI2. XL3. XVII4. DCCLVI5. MCMLXIX

Click on the number that matches the Roman Numeral.

1.LXIII

A. 53

B. 63

C. 113

OOPS! Try again!

You are correct! LXIII = 50+10+3 = 63

L=50; X=10; III=3

Remember:

2.DCXXIV

A. 624

B. 1624

C. 5524

OOPS! Try again!

You are correct! DCXXIV= 500+100+20+4=

624

3. CCL

A. 150

B. 250

C. 550

OOPS! Try again!

You are correct! CCL = 100+100+50=250