3-Digit Numbers Class 2 Notes Maths

Counting 3 Digit Numbers

Three-digit numbers in terms of hundreds can be written as:

• 10 tens = 100 or 1 hundred
• 20 tens  = 200 or 2 hundreds
• 30 tens  = 300 or 3 hundreds
• 40 tens  =  400 or 4 hundreds
• 50 tens  =  500 or 5 hundreds
• 60 tens  =  600 or 6 hundreds
• 70 tens  =  700 or 7 hundreds
• 80 tens  =  800 or 8 hundreds
• 90 tens  =  900 or 9 hundreds
• 100 tens  =  1000 or 10 hundreds = 1 thousand

Do you know?

• 1000 is the smallest 4-digit number. 
• 999 is the largest 3-digit number. 
• 100 is the smallest 3-digit number. 
• 99 is the largest 2-digit number.

Place Value of a Number

The place value of a digit depends on the position of the digit in the place value chart:

• The place value of 4 is 4 hundred or 400.
• The place value of 6 is 6 tens or 60.
• The place value of 9 is 9 ones or 9.

Face Value of a Number

In a numeral, the face value of a digit is the actual value of the digit, at whatever places it may be.

Thus, in the numeral 569, 

• the face value of 5 is 5;
• the face value of 6 is 6; 
• the face value of 9 is 9.

Expanded Form of Numbers

To express a number as a sum of place values of its digits is called expanded form.

In the numeral 29,

Q.1. Write 4 8 2 in expanded form.

Comparison of Three-Digit Numbers

To compare 3-digit numbers, first we compare the digits at the hundreds place and then tens place and at last the ones place.

Let us compare the numbers 528 and 536.
Which one is lesser?

Here digits at hundreds places in both the numbers are same. So, we compare tens place digits of both numbers.
Since 2 < 3
So, 528 < 536.
We say that 528 is less than 536.

Let us now compare 782 and 789. Which one is greater?

Digits at hundreds and tens places in both the numbers are same. So, we compare digits at ones place.
Since 9 > 2
So,  789 > 782.
We say that 789 is greater than 782.

Note: A one-digit number < a two-digit number < a three-digit number.

Ascending and Descending Order

Ascending order: Ascending is increasing (i.e., small → big).

Example: Arrange these numbers in ascending order (i.e., smallest to greatest).  
498, 567, 834, 715

In the above numbers, the smallest number is 498 and the greatest number is 834.
Ascending order is: 498, 567, 715, 834
or
498 < 567 < 715 < 834

Descending order: Descending is decreasing (i.e., big → small).

Example: Arrange these numbers in descending order (i.e., biggest → smallest).
826, 736, 582, 914

In the above numbers, the largest number is 914 and the smallest number is 582.

Descending order is: 914, 826, 736, 582
or
914 > 826 > 736 > 582

Even and Odd Numbers

Even numbers

Let us take a collection of 6 apples.

Group these apples into pairs (i.e., set of 2 apples each).

Is there any apple left? No.
So, 6 can be fully grouped into pairs. Such numbers which can be fully grouped into pairs are called even numbers.

Note: Even numbers have 0, 2, 4, 6 or 8 at ones place.

Odd numbers

Let us take a collection of 7 oranges.

Group these oranges into pairs (i.e., set of 2 oranges each).
Is there any orange left? Yes, one.
So, 7 cannot be fully grouped into pairs.
Such numbers which cannot be fully grouped into pairs are called odd numbers.

Note: Odd numbers have 1, 3, 5, 7 or 9 at ones place.