Adding and Subtracting Roman Numerals

1. Adding and SubtractingRoman Numerals Author: Matt Hampton CS 255 http://ellerbruch.nmu.edu

2. Let’s ReviewThe Basic Values of Roman Numerals • I = one (1) • V = five (5) • X = ten (10) • L = fifty (50) • C = one hundred (100) • D = five hundred (500) • M = one thousand (1,000)

3. Review of Reading Roman Numerals • If a smaller numeral follows AFTER a larger numeral, such as (12) then add the value of the numerals together. • Example: • XII means 10 + 2 = 11 • If a smaller numeral comes BEFORE a larger numeral, such as (4) then subtract the value of the smaller from the value of the larger numeral. • Example: • IV means 5 – 1 = 4

4. 3 Easy Steps To Adding and SubtractingRoman Numerals • Break Down the Problem • Bring them Together • Answer

5. Now Let’s Try Adding Roman Numerals • Here is an Example of adding two Roman Numerals. • Ex. IV + II = VI 1st) Break down the problem. 3rd) Answer. IV = 5 – 1 = 4 IV + II = VI, 6 II = 1 + 1 = 2 2nd) Bring them together. (5 – 1) + (1 + 1) = 5 – 1 = 4 1 + 1 = 2 4 + 2 = 6

6. Now Let’s Try Subtracting Roman Numerals • Here is an Example of subtracting two Roman Numerals. • Ex. VII - II = V 1st) Break it down. 3rd) Answer. VII = 5 + 2 = 7 VII - II = V, 5 II = 1 + 1 = 2 2nd) Bring them together. (5 + 2) - (1 + 1) = 5 + 2 = 7 1 + 1 = 2 7 - 2 = 5

7. Sources • Imakewebsites. Roman Numerals. 20, April 2004. http://www.romannumerals.co.uk • Ask Dr. Math. 1994-2004 The Math Forum. 21, April 2004.http://mathforum.org