Page 19 - Math Skill - 4

Numbers 17

On the number line, 8250 is nearer to 8000, so we round off 8250 to 8000.

On the number line, 8750 is nearer to 9000, so we round off 8750 to 9000.

Thus, the rules for rounding off a number to the nearest thousand are as follows:

™ If the digit at hundreds place is less than 5, replace the digits at hundreds, tens and ones
places by 0 and keep all the other digits as they are.

™ If the digit at hundreds place is 5 or greater than 5, increase the digit at thousands place
by 1 and replace the digits at hundreds, tens and ones places by 0.

Let’s Attempt

Example: Round off each of the following numbers to the nearest thousand.
(a) 7487 (b) 12639
Solution: (a) The given number is 7487.
Its hundred digit place is 4 and 4 < 5.

Thus, 7487 is rounded off to 7000.
(b) The given number is 12639.
Its hundred digit is 6 and 6 > 5.
Thus, 12639 is rounded off to 13000.

Exercise 1.7

1. Round off each of the following numbers to the nearest ten.
(a) 75 (b) 152 (c) 98 (d) 1658
2. Round off each of the following numbers to the nearest hundred.

(a) 778 (b) 7852 (c) 97752 (d) 16728

3. Round off each of the following numbers to the nearest thousand.
(a) 1789 (b) 78569 (c) 12345 (d) 75898

Roman Numerals
Numerals are used to represent numbers. 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9 are Hindu-Arabic numerals.

Roman numerals is other system of writing numbers. It has seven basic symbols.

Roman Numerals I V X L C D M

Hindu-Arabic Numerals 1 5 10 50 100 500 1000

It has no place value system and it has no symbol for 0.
We have learnt reading and writing Roman numerals up to 20 in the previous class.

Let us extend the system to read and write up to 100.