Medical Math

Health Occupations EducationMrs. Rose

Roman Numerals

• Used for some drugs and solutions• Sometimes used when ordering supplies

Key Numerals

• I• V• X• L• C• D• M

• 1• 5• 10• 50• 100• 500• 1000

• Any number can be formed by using these numerals

• No more than three of any one Roman numeral is used to represent a number.

• Example– I 1 x 10– II 2 xx 20– III 3 xxx 30

Rules to remember

• If a numeral for smaller numbers are used after a numeral for larger numbers, all the numbers are added together

• Example– VII 5+1+1 = 7– XI 10+1=11– LXX 50+10+10=70– MCL 1000+100+50=1150

• If the numeral for a smaller number is used in front of the numeral for a larger number, the smaller number is subtracted from the larger number

• Example– IX 1 is before 10 (subtract) 10-1=9– XC 10 is before 100 100-10=90– CD 100 is before 500 500-100=400

Practice

• 1. XXV 6. XLVI• 2. LIV 7. XVII• 3. XIV 8. LXXVII• 4. XXIV 9. XIII• 5. XCI 10. LXXII

Larger Roman Numerals

• When reading larger numbers, distinguish the subtracted numbers before adding up the values

• Example add– DCXLIX 500• D-500 100• C-100 649• XL 50-10=40 40• IX 10-1=9 9

PRACTICE

• MMCMXXCVII

• M 1000• M 1000• CM 900 (100 before 1000)• XXC 80 (20 before 100)• V 5• I 1• I 1

• Answer is 2,987

HOW TO WRITE THEM

Break down the numbers in basic components beginning with the largest number

Example ---- 273200+70+3Break them down again100+100+50+10+10+1+1+1CCLXXIII

MORE PRACTICE BREAKING DOWN

• 400• 100+100+100+100• Remember the rule----no more than three so

go the next highest• 500 with 100 before it 500-100=400• 400 = CD

Another rule to remember

• A bar is placed over a roman numeral indicates that roman numeral x 1000

• Example ___ M M = 1000 X 1000 1,000,000

• __ XX=10 X 100010,000