Decimals :-
Observe below number
382.724 1st part =
382 = integral part
2nd part = .
724 = decimal part
The small dot in between the digits 2 & 7 is called decimal point. Such a number is called Decimal Point.
Hundreds
(100) | Tens
(10) | Ones
(1) | Tenths
(1/10) | Hundredths
(1/100) | Thousandths
(1/1000) | Number |
| 3 | 8 | 2 | 7 | 2 | 4 | 382.724 |
Expanded Form :-
382.724 = 3 x 100 + 8 x 10 + 2 x 1 + 7 x (1/10) + 2 x (1/100) + 4 x (1/1000).
| Position after decimal point | Represents | Called |
| First position after decimal point | Tenths | First decimal place |
| Second position after decimal point | Hundredths | Second decimal place |
| Third position after decimal point | Thousandths | Third decimal place |
Like and Unlike decimal Numbers :-
Decimal Numbers :- The decimal numbers having equal number of decimal places. e.g. 2.11, 584.72,
Unlike Decimal Numbers :- The decimal numbers having different number of decimal places. e.g. 4.2, 312.011,
Comparison of decimal numbers :-
1) Express given decimal numbers as like decimal numbers.
2) The decimal number having greater whole number part is greater.
3) If whole number part is equal, compare tenth digits- the number having greater tenth digit is greater.
If thenth digits are equal, compare digits at hundredths place- the number having greater hundredth digit is greater.
e.g find which number is greater?
319.72 , 319.75
1)These are like decimal numbers & whole number parts are equal.
2) Compare tenth digits. In both numbers, digit at thenths place = 7
3)Compare hundredth digits.
In 319.72, digit at hundredths place = 2
In 319.75, digit at hundredths place = 5
since 5 > 2, hence 319.72 < 319.75
Addition of decimal numbers :-
Write the given decimal numbers one below the other such that decimal points of both numbers lie below each other, then add numbers as usual.
Subtraction of decimal numbers :-
Write the decimal number which is to be subtracted below the other number such that decimal points of both numbers lie below each other, then subtract numbers as usual.