Rules of Roman Numeration

We will learn about Roman Numeration and its rules. We know that there are seven basic Roman Numerals. They are I, V, X, L, C, D and M. These numerals stand for the number 1, 5, 10, 50, 100, 500 and 1000 respectively. We already learned about the numerals I, V, X, L and C and now we will learn about the remaining two numerals.

There is another symbol ‘─’ which is called bar. If bar is place over a numeral, it is multiplied by 1000. Thus, V and XII stand for 5000 and 12000 respectively.

Rules of Roman Numeration:

1. Numerals of the same value are added.

For example:

I I I stands for 1 + 1 + 1 = 3

X X X stands for 10 + 10 + 10 = 30

C C C stands for 100 + 100 + 100 = 300

M M M stands for 1000 + 1000 + 1000 = 3000

Note:

(i) Symbols V, L and D are not repeated.

(ii) A symbol cannot be repeated more than three times.

2. A symbol of smaller value put on the right of greater value symbol is added to it.

For example:

VI stands for 5 + 1 = 6

CXX stands for 100 + 10 + 10 = 120

MCL stands for 1000 + 100 + 50 = 1150

3. A symbol of smaller value put on the left of greater value symbol is subtracted from it.

For example:

IV stands for 5 - 1 = 4

IX stands for 10 - 1 = 9

XL stands for 50 - 10 = 40

Note:

(i) Symbol V, L and D are never subtracted.

(ii) Symbol I can be subtracted from V and X only.

(iii) Symbol X can be subtracted from L and C only as L and C are greater than X.

(iv) Symbol C can be subtracted from D and M.

4. A symbol of smaller value, put between two symbols of greater value is subtracted from the symbol on its right.

For example:

XIV stands for 10 + 5 - 1 = 14

LIX stands for 50 + 10 - 1 = 59

XCIX stands for 90 + 10 - 1 = 99

XLIX stands for 40 + 10 - 1 = 49

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5th Grade Math Problems

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