1. Decimal Numbers with Equal Decimal Digits 2. Decimal Numbers with Unequal Decimal Digits

**Comparison of Decimals**

Let us see Bob Beamon's Long Jump record
of 1968 summer Olympics which stood for 23 years. His record was 8.90 *m*.
This record was broken by Carl Lewis and Mike Powell in 1991,World championship
held at Tokyo, Japan. Carl Lewis jumped 8.91 *m* and Powell jumped 8.95 *m*.
Can you compare these distances?

We follow these steps to compare decimals.

** **

__1. Decimal Numbers with Equal Decimal Digits__

**Step:1 **Compare the whole number part of the
two numbers.

The decimal number that has the greater
whole number part is greater.

**Step:2** If the whole number part is equal, then
compare the digits at the tenths place. The decimal number that has the larger tenths
digit is greater.

**Step:3** If the whole number part and the digits
at the tenths place are equal, compare the digits at the hundredths place. The decimal
number that has the larger hundredth digit is greater. The same procedure can be
extended to any number of decimal digits.

** **

__2. Decimal Numbers with Unequal Decimal Digits__

Let us now compare the numbers 45.55
and 45.5. In this case, we first compare the whole number part. We see that the
whole number part for both the numbers are equal. So, we now compare the tenths
place. We find that for 45.55 and 45.5, the tenth place is also equal. Now we proceed
to compare hundredth place. The hundredth place of 45.5 is 0 and that of 45.55 is
5. Comparing the hundredths place, we get 0 <
5.

Therefore, 45.50 < 45.55

**Note **

Zeros added to the right
end of decimal digits do not change the value of that decimal number.

** **

__Example 1.13__

Velan bought 8.36** ***kg*** **of potato and Sekar bought
6.29** ***kg*** **of potato. Which** **is heavier?

**Solution**

Compare 8.36 and 6.29

Comparing the whole number part, we get
8 > 6.

Therefore, 8.36
> 6.29

** **

__Example 1.14 __

Two automatic ice cream machines
A and B designed to fill cups with** **100 *ml* of ice cream were tested. Two cups of ice creams, one
from machine A and one from machine B are weighed and found to be 99.56 *ml*
from machine A and 99.65 *ml* from machine B. Can you say which machine gives
more quantity of ice creams?

**Solution**

Compare 99.56 and 99.65

Here the whole number parts of the given
two numbers are equal.

Comparing the digits at tenths place,
we get 5 < 6.

Therefore, 99.56 < 99.65

** **

__Example 1.15 __

A standard art paper is about
0.05* mm*** **thick and matte coated paper is** **0.09* mm* thick. Can you say
which paper is more thick?

**Solution**

Compare 0.05 and 0.09

By using the steps given above, the integral
parts and tenths places are equal. By comparing the hundredth place, we get 5 < 9. Therefore,
0.05 < 0.09.

So far we discussed about the comparison
of two decimal numbers. Extending this, we can arrange the given decimal numbers
in ascending or descending order.

** **

__Example 1.16 __

Now let us arrange the long
jump records of students in a school for** **3 years in ascending order

(i) 1 year -4.90 *m*

(ii) 2 year-4.91 *m*

(iii) 3 year-4.95 *m*

**Solution**

The whole number parts of the three decimal
numbers are equal.

The digits at tenths place are also equal.

The digits at hundredths place are 0, 1 and 5.
Here 0 <1 <5

Therefore, the ascending order is 4.90, 4.91, 4.95.

**Note**

The descending order is
4.95,4.91,4.90

** **

__Example 1.17____ __

Megala and Mala bought two watermelons
weighing 13.523* kg *and 13.52 *kg*. Which is a heavier one?

**Solution**

In this case, the two numbers have same
digits upto hundredths place. But the thousandth place of 13.523 is 3, which is
greater than 0, which is the thousandth place of 15.32.

So, 13.523
> 13.520

**Note**

3.300 and 3.3 are the same.

3.300 = 3.3

Tags : Number System | Term 2 Chapter 1 | 7th Maths , 7th Maths : Term 2 Unit 1 : Number System

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7th Maths : Term 2 Unit 1 : Number System : Comparison of Decimals | Number System | Term 2 Chapter 1 | 7th Maths

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