Kavitha went shopping and saw prices like 299.00 and 32.99 on bills, which are decimal numbers. Decimal numbers have three parts: a whole number, decimal point, and decimal part. The decimal part represents fractions of ones - numbers after the decimal point indicate tenths, hundredths, thousandths and so on. Decimal numbers can be represented pictorially using boxes and sheets to show their place value or in an expanded form that multiplies the place value of each digit.

1. DECIMAL
NUMBERS

2.  Kavitha went to shopping to buy clothes for her family and she came
 to the cash counter to pay the bill
 In the bill the price of watches is represented by 299.00 and the price of socks
is 32.99
 The numbers 299.00 and 32.99 are known as decimal numbers

3. DECIMAL NUMBERS
A decimal is a fraction written in a special form.
DECIMAL
LATIN WORD
DECIMUS
TENTH

4. PARTS OF DECIMAL NUMBERS
45 . 99
WHOLE PART
OR
INTEGRAL
PART
DECIMAL
POINT
DECIMAL
PART

5. PICTORIAL REPRESENTATION OF DECIMAL
NUMBERS
 The decimal number 12.2 can be represented pictorially as follows:
 The whole part 12 is represented by 12 boxes which is depicted by 10 boxes which comes
under tens place and then two boxes which comes under ones place
 again one box according to place value
 The decimal part 2 is represented by sheets of 2
• This is read as 10 tens 2 ones and 2 tenths.

6. • This shaded region can be expressed in fraction
form as 1 in which the denominator can be
5
converted into powers of 10 and represented into
decimal form as 0.2

7. EXPANDED FORM OF A NUMBER AND
DECIMAL NUMBER
NUMBERS
3768
The number can be expanded in the form
3 x 1000 + 7 x 100 + 6 x 10 + 8
DECIMAL NUMBERS
235.68
The number can be expanded in the form
2 x 100 + 3 x 10 + 5 x 1 + 6×
1
10
+ 8 ×
1
100

8. REPRESENTATION
OF A NUMBER IN
PLACE VALUE GRID
Thousands Hundreds Tens Ones
3 7 6 8
3768

9. REPRESENTATION OF
DECIMAL NUMBERS IN
PLACE VALUE GRID
Tens Ones Tenths
2 5 6
25.6

10. SUMMARY
• Decimal is derived from the latin word ‘decimus’ which means tenth
• Decimal number has three parts whole number, decimal point and decimal part
• Fraction can be converted into decimals by converting the denominator inton powers of 10
• The number after the decimal point in the place value is read as tenth, hundredth and
thousandth

11. ACTIVITIES
1. Represent the decimal numbers pictorially 5 ones and 3 tenths
2. Write the place value of underlined digits 35.677
3. Write the decimal number in the place value grid 9.675
4. Collect pictures of bills and paste in the notebook
5. Name the parts of decimal numbers