Decimals are used in situations where more precision is required in comparison to the whole numbers. For example, when we have to divide 3 apples among 4 kids, we cannot use whole numbers to denote the resultant of the division, as the fraction of share that is 0.75 lies between 0 and 1. In order to deal with similar other systems, the concept of decimal was introduced.
A decimal number is a number where the integer part is separated from the fractional part with the help of a decimal point. The digits are placed to the left and to the right of the decimal to represent numbers greater than or less than one.
There are certain rules to be followed while reading a decimal number. For e.g. 1.23 is read as one point two three and not one point twenty three.
In order to understand the concept of decimals, let us make a square table with 1 row and 10 columns, as shown in the figure.
Let us fill four of these blocks, as shown below
The fraction of colored blocks to the total blocks can be written as 4/10. Another representation for the same can be given in terms of decimals, as 0.4. Here 0.4 = 4 * or can be written as 4 tenths.
Similarly if we take a square of 10 rows and 10 columns, we get 100 small squares. If we color 27 of these blocks, the fractional representation can be written as 27/100.
Here 27/100 = 27*1/100 = 27 hundredth which is represented in the decimal form as 0.27.
So when we have a number 2.34, it is equivalent to 2 + 3tenths and 4 hundredths.
Representation of decimal on the number line
We know how to represent whole numbers on the number line. Let us consider the image shown. Here, the digits 0 and 1 are represented on the number line.
If we divide the number line into two equal parts, as shown in the figure below, what value does mid-point hold? We will say half of what the graduation between 0 and 1 holds.
So, the point represents (1-0)/2 = 0.5
In order to represent decimal on the number line, we divide the section between two whole numbers as per the places after decimal present in the number to be represented.
Example 1: Represent 0.8 on the number line
As we know, the number 0.8 is equivalent to 8 tenths, so we divide the section between 0 and 1 into 10 equal parts. Now, stepping 8 points from 0 towards 1 gives us 0.8.
Example 2: Represent 8.6 on the number line.
The number 8.6 = 8 + 0.6
We start from the number 8 on the number line and divide the section between 8 and 9 into 10 equal parts. Now, taking 6 steps from 8 towards 9 helps us represent 8.6
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