Maharashtra Board Class 5 Mathss Part One Chapter 1 Roman Numerals PDF Download

Roman Numerals

Geeta: This clock doesn't have numbers. It has some symbols instead.

Teacher: Yes, Geeta! These are Roman numerals. In Europe, in the old times, Roman capital letters were used to write numbers. That is why, they were called Roman numerals. The letter 'I' was the symbol used for 1, 'V' for 5, and 'X' for 10.

In this method, there was no symbol for zero. Also, the value of a symbol did not change with its place. There are certain rules for writing numbers using the Roman numerals. Let us see how to write 1 to 20 using these rules and the symbols I, V and X.

Rule 1

If either of the symbols I or X is written consecutively two or three times, their sum total is the number they make.

Examples: II = 1 + 1 = 2, XX = 10 + 10 = 20, III = 1 + 1 + 1 = 3

Rule 2

The symbols I or X can be repeated consecutively for a maximum of three times. The numeral V is never repeated consecutively.

Rule 3

When either I or V is written on the right of the symbol of a bigger number, its value is added to the value of the bigger number.

Examples: VI = 5 + 1 = 6, XI = 10 + 1 = 11, XV = 10 + 5 = 15

VII = 5 + 2 = 7, XII = 10 + 2 = 12, XVI = 10 + 5 + 1 = 16

VIII = 5 + 3 = 8, XIII = 10 + 3 = 13

Rule 4

When I is written on the left of V or X, then its value is subtracted from the value of V or X. However, the symbol I is not written more than once before V or X.

Examples: IV = 5 – 1 = 4, IX = 10 – 1 = 9. But, the number 8 is not written as IIX.

We have to think a little differently to write the numbers 14 and 19.

14 = 10 + 1 + 1 + 1 + 1. However, we do not use the symbol I consecutively more than 3 times. Hence, we shall think of the number 14 as 10 + 4, instead. Then, using the symbol IV for 4, we write 14 as XIV. Similarly, we shall think of the number 19 as 10 + 9 and write it as XIX.

Thus, to write the numbers from 1 to 20 in Roman numerals, we first distribute a given number into groups of 10, 5 and 1 and then apply the rules given above.

Thus, 12 = 10 + 1 + 1 = XII, 7 = 5 + 1 + 1 = VII, 18 = 10 + 5 + 3 = XVIII

Teacher's Note

Roman numerals were used a long time ago in Europe. You can see them on old clock faces and in history books. In India, we use our decimal numbers now, but it is good to know about Roman numerals too.

Exam Trick

Remember: When I comes before V or X, you subtract it. IV = 4 (not 6), and IX = 9 (not 11). Think of it like taking away, not adding.

Points to Remember

Roman numerals use I, V, and X for numbers 1 to 20.
I = 1, V = 5, X = 10.
I and X can be used up to 3 times in a row, but V is never repeated.
When a smaller number is on the left, you subtract it from the bigger number.
There is no zero in Roman numerals.

Problem Set 1

1. Write all the numbers from 1 to 20 using Roman numerals.

2. Write the following numbers using international numerals.

(1) V (2) VII (3) X (4) XIII (5) XIV (6) XVI (7) XVIII (8) IX

3. Fill in the empty boxes.

4. Write the numbers using Roman numerals.

(1) 9 (2) 2 (3) 17

(4) 4 (5) 11 (6) 18

5. In the table below, each given number is written in international numerals and then again in Roman numerals. If it is written correctly in Roman numerals, put a check mark in the box under it. If not, put an X and correct it.

Something more: L, C, D and M are also used as Roman numerals.

Activity: Apart from clocks and watches, where else do we see Roman numerals?

Teacher's Note

Roman numerals are used in many places in India. You can see them on old buildings, monuments, and books. Even today, sometimes we use them for numbering chapters or important events.

Exam Trick

To check if a Roman numeral is correct, count how many times each letter repeats. Remember: I, X, and C can repeat only 3 times. V, L, and D can never repeat.

Points to Remember

L means 50, C means 100, D means 500, and M means 1000.
Always check the rules before writing Roman numerals.
Roman numerals are not easy for doing math.
Practice writing Roman numerals for numbers 1 to 100.
Pay attention to the position of each letter in the numeral.

The Decimal System Of Writing Numbers

It is not easy to read or write numbers using Roman numerals. It also makes calculations difficult. You have learnt to write numbers using the ten digits, 0 to 9. In that system, the value of a digit depends upon its place in the number. This system of writing numbers is called the 'decimal system'.

Mathematicians of ancient India invented the decimal system of writing numbers and began to use it. Later, this system was accepted in all parts of the world because it was simple and convenient.

Teacher's Note

India gave the world the decimal system and the number zero. This was a big gift to the whole world. Without this system, we could not do math, science, or computers today.

Exam Trick

Remember: The decimal system has 10 digits (0, 1, 2, 3, 4, 5, 6, 7, 8, 9). It is called decimal because "deci" means 10. The decimal system is easy and used all over the world.

Points to Remember

The decimal system uses 10 digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9.
In this system, the place of a digit gives it its value.
The decimal system was invented by ancient Indian mathematicians.
It is easier than Roman numerals for doing math and calculations.
Today, the whole world uses the decimal system.

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