Introduction: What are Decimals in Maths?
A decimal is defined as a number expressed in decimal notation and generally applied to values that have a fractional part and separated from the integer side by a decimal separator.
Now let’s see an example
Here is the number “thirty-four and seven-tenths” written as a decimal number:
The decimal point goes between Ones and Tenths
34.7 has 3 Tens, 4 Ones and 7 Tenths
Place Value in decimals
The place value system is used to define the position of a digit in a number which helps to determines its value. When we write specific numbers, the position of each digit is important.
Example:
For instance, let’s consider the number 456.
- The position of “6” is in One’s place, which means 6 ones (i.e. 6).
- The position of “5” is in the Ten’s place, which means 5 tens(i.e. fifty).
- The position of “4” is in the Hundred’s place, which means 4 hundred.
- As we go left, each position becomes ten times greater.
Hence, we read it as “Four hundred fifty-six”.
As we move left, each position is 10 times bigger!
Tens are 10 times bigger than Ones.
Hundreds are 10 times bigger than Tens.
And
Each time we move right every position becomes 10 times smaller
From Hundred’s to Ten’s, to Ones
But if we continue past Ones?
What is 10 times smaller than Ones?
\(\frac{1}{10}ths\) (Tenths) are!
Before that, we should first put a decimal point,
So we already know that where we put that decimal point.
We say the above example as four hundred and fifty-six and eight-tenths but
We usually just say four hundred and fifty-six point eight.
Types of Decimal Numbers
Decimal Numbers may be of different kinds, namely
Recurring Decimal Numbers (Repeating or Non-Terminating Decimals)
Example-
3.125125 (Finite)
3.121212121212….. (Infinite)
Non-Recurring Decimal Numbers (Non Repeating or Terminating Decimals):
Example:
3.2376 (Finite)
3.137654….(Infinite)
Decimal Fraction- It represents the fraction whose denominator in powers of ten.
Example:
81.75 = 8175/100
32.425 = 32425/1000
Converting the Decimal Number into Decimal Fraction:
For the decimal point place a “1” in the denominator and remove the decimal point.
“1” is followed by a number of zeros equal to the number of digits following the decimal point.
For Example:
8 1 . 7 5
↓ ↓ ↓
1 0 0
81.75 = 8175/100
8 represents the power of 10^{1} that is the tenths position.
1 represents the power of 10^{0 }that is the units position.
7 represents the power of 10^{-1} that is the one-tenths position.
5 represents the power of 10^{-2} that is the one-hundredths position.
So that is how each digit is represented by a particular power of ten in the decimal number.
Place Value of Decimal Numbers
The place value is obtained by multiplication of the digit in the decimal number with its power of ten that the digit holds at its position.
Place Value Chart
The power of ten can be found using the following Place Value Chart:
The digits to the left of the decimal point are multiplied with the positive powers of ten in increasing order from right to left.
The digits to the right of the decimal point are multiplied with the negative powers of 10 in increasing order from left to right.
Following the same example 81.75
The decimal expansion of this is :
{(8*10)+(1*1)} + {(7*0.1)+(5*0.01)}
Where each number is multiplied by its associated power of ten.
Related Links | |
Decimals Word Problems | Square Root Of Decimals |
Addition And Subtraction In Decimals | Application of Decimals in Daily Life |
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I want Maths question paper of decimal
Here you could find the Decimal question paper for Class 6 and 7 – https://byjus.com/maths/decimal-worksheets/