The Facts On File Algebra Handbook

Roman Numerals – Signed Numbers CHARTS & TABLES

Roman Numerals – Signed Numbers CHARTS & TABLES

Roman Numerals (continued)

Repeating

If a numeral repeats itself, the value is repeated. II is 2, or two times one. XX is 20,

or two times 10. CC is 200, or two times 100. The Roman numerals L, V, and D are

not written in a repeating sequence because LL is the same value as C (50 times 2 is

the same as 100), VV is the same as X (5 times 2 is the same as 10), and DD is the

same as M (500 times 2 is the same as 1,000).

II 2

III 3

XX 20

XXX 30

MM 2,000

MMM 3,000

Bar

If the Roman numeral has a bar above it, the value increases by 1,000. ̄V is 5,000, ̄IV

is 4,000, etc.

Signed Numbers

Absolute Value

The absolute value of a signed number is the number without the sign. For example:

|–5|= 5

|+27|= 27

Adding Signed Numbers

Adding two positives equals a positive.

Adding two negatives equals a negative.

To add a positive and negative:

a. Make both numbers absolute values

b. Subtract the smaller number from the larger number

c. Put the sign of the larger original number in front of the difference

For example:

5 + –12

a. | 5 |+|–12|

b. 12 – 5 = | 7 |

c. –7

(continues)