Do we know from where Roman symbols came? In Rome, people wanted to use their own symbols to express various numbers. These symbols, used by Romans, are known as Roman symbols, Romans used only seven symbols V, X, L, C, D, M to express different numbers.
The Roman numeration system, developed by Romans, is based on these 7 Roman digits. We use these Roman digits to express different Roman numbers.
What are Roman numbers?
Roman symbols - I, V, X, L, C, D, M stand for different Roman numbers.
I stand for 1
V stands for 5
X stands for 10
L stands for 50
C stands for 100
D stands for 500
M stands for 1000
We know in some clocks the Roman symbols marked on some of
the dials of the clocks. We follow some rules to express Roman numbers.
1. We can use I and X thrice only in a numeral.
For example, we write I, II, III, for 1, 2, 3 respectively but we never write IIII for 4. We write IV for 4.
2. We never repeat V, L and D. They are used in a numeral once only.
For example, we never write VV for 10. We write X for 10.
3. When we write smaller numeral to the left of the greater numeral it means that the smaller numeral is subtracted from the greater one.
Let us consider some examples.
IV means V - I
= 5 - 1 = 4
IX means X - I
= 10 - 1 = 9
XL means L - X
= 50 - 10 = 40
4. When we write a smaller numeral to the right of a greater numeral it means that the smaller numeral is added to the greater one.
VI means V + I
= 5 + 1 = 6
XV means X + V
= 10 + 5 = 6
VII means V + II
= 5 + 2 = 7
LX means L + X
= 50 + 10 = 60
5. We never write V to the left of X. Similarly, L and D are never written to the left to any other symbol.
For example, we write XV for 15 but we never write VX for 5. We write LV for 55 but we never write LC for 50.