EQ How do you read and write Roman
- Slides: 23
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 1 st 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 • C = 100 • V = five • D = 500 • X = ten • M = 1, 000 • L = fifty 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 XXXXX (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
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 Problem 1. 23 + 58
Answer to the Adding Problem Step 1. Step 2. Step 3. Step 4. Step 5. Step 6. Step 7. Step 8. 23 + 58 XXIII + LVIII XXIIILVIII LXXVIIIIII = VI LXXVVI VV = X LXXXI = 81 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. 2. 3. 4. 5. XXXVI XL XVII DCCLVI 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 Remember: L=50; X=10; III=3
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+50=250
