NON RECURRING DECIMALS

About "Non recurring decimals"

What is  "non recurring decimals" ? 

The decimal numbers which continue infinitely without repeated pattern.  

Non recurring decimals - Examples 

All the above decimal numbers are irrational and they can not be converted into fractions. 

How do we have this non repeating decimal in math ?

When we are trying to find square of a number which is not a perfect square, we get this non repeating non terminating decimal.

And these decimals can never be converted in to fractions and they are called as irrational numbers. 

When can we convert a non terminating decimal into fraction ?

A non terminating decimal can be converted into fraction, only if it has repeated pattern. 

More clearly, 

Non terminating recurring decimals can be converted into fractions. 

Non terminating non recurring decimals can never be converted into fractions.

How to convert non terminating repeating decimal to fraction?

Step 1 : 

Let  x = Given decimal number 

For example,

If the given decimal number is 2.0343434.........

then, let x = 2.0343434...........

Step 2 : 

Identify the repeated pattern

For example,

In 2.0343434..........., the repeated pattern is 34

(Because 34 is being repeated)

Step 3 :

Identify the first repeated pattern and second repeated pattern as as explained in the example given below. 

Step 4 :

Count the number of digits between the decimal point and first repeated pattern as given in the picture below. 

Step 5 :

Since there is 1 digit between the decimal point and the first repeated pattern, we have to multiply the given decimal by 10 as given in the picture below. 

(If there are two digits -----------> multiply by 100,

three digits -----------> multiply by 1000  and  so on )

Note : In (1), we have only repeated patterns after the decimal.

Step 6 : 

Count the number of digits between the decimal point and second repeated pattern as given in the picture below.

Step 7 :

Since there are 3 digits between the decimal point and the second repeated pattern, we have to multiply the given decimal by 1000 as given in the picture below. 

Note : In (2), we have only repeated patterns after the decimal.

Step 8 :

Now, we have to subtract the result of step 5 from step 7 as given in the picture below. 

Now we got the fraction which is equal to the given decimal

Some more problems

To have better understanding on conversion of non terminating repeating decimals to fraction, let us look at some problems.

Problem 1 :

Covert the given non terminating repeating decimal into fraction

32.03256256256..........

Solution : 

Let X = 32.03256256256.............

Here, the repeated pattern is 256

No. of digits between the 1st repeated pattern and decimal = 2

So, multiply the given decimal by 100. Then, we have

100X = 3203.256256256...............----------(1) 

No. of digits between the 2nd repeated pattern and decimal = 5

So, multiply the given decimal by 100000. Then, we have

100000X = 3203256.256256256...............----------(2)

(2) - (1) --------> 99900X = 3200053

X = 3200053 / 99900

Hence, 32.03256256256.......... =  3200053 / 99900

Problem 2 :

Covert the given non terminating repeating decimal into fraction

0.01232222........

Solution : 

Let X = 0.01232222.............

Here, the repeated pattern is 2

No. of digits between the 1st repeated pattern and decimal = 4

(Here, the first repeated pattern starts after four digits of the decimal)

So, multiply the given decimal by 10000. Then, we have

10000X = 123.2222...............----------(1) 

No. of digits between the 2nd repeated pattern and decimal = 5

So, multiply the given decimal by 100000. Then, we have

100000X = 1232.2222...............----------(2)

(2) - (1) --------> 90000X = 1109

X = 1109 / 90000

Hence, 0.01232222........... =  1109 / 90000

Problem 3 :

Covert the given non terminating repeating decimal into fraction

2.03323232..........

Solution : 

Let X = 2.03323232.............

Here, the repeated pattern is 32

No. of digits between the 1st repeated pattern and decimal = 2

(Here, the first repeated pattern starts after two digits of the decimal)

So, multiply the given decimal by 100. Then, we have

100X = 203.323232...............----------(1) 

No. of digits between the 2nd repeated pattern and decimal = 4

So, multiply the given decimal by 10000. Then, we have

10000X = 20332.323232...............----------(2)

(2) - (1) --------> 9900X = 20129

X = 9900 / 20129

Hence, 2.03323232.......... =  9900 / 20129

Problem 4 :

Covert the given non terminating repeating decimal into fraction

0.252525..........

Solution : 

Let X = 0.252525.............

Here, the repeated pattern is 25

No. of digits between the 1st repeated pattern and decimal = 0 

So, multiply the given decimal by 1. Then, we have

X = 0.252525...............----------(1) 

No. of digits between the 2nd repeated pattern and decimal = 2

So, multiply the given decimal by 100. Then, we have

100X = 25.252525...............----------(2)

(2) - (1) --------> 99X = 25

X = 25 / 99

Hence, 0.252525.......... =  25 / 99

Problem 5 :

Covert the given non-terminating repeating decimal into fraction

3.3333..........

Solution : 

Let X = 3.3333.............

Here, the repeated pattern is 3

No. of digits between the 1st repeated pattern and decimal = 0

(Here, the first repeated pattern is "3" which comes right after the decimal point)

So, multiply the given decimal by 1. Then, we have

X = 3.3333...............----------(1) 

No. of digits between the 2nd repeated pattern and decimal = 1

(Here, the second repeated pattern is "3" which comes one digit  after the decimal point)

So, multiply the given decimal by 10. Then, we have

10X = 33.3333...............----------(2)

(2) - (1) --------> 9X = 30

X = 30 / 9 = 10 / 3

Hence, 3.3333.............. =  10 / 9

Problem 6 :

Covert the given non-terminating repeating decimal into fraction

1.023562562562..........

Solution : 

Let X = 1.023562562562.............

Here, the repeated pattern is 562

No. of digits between the 1st repeated pattern and decimal = 3 

So, multiply the given decimal by 1000. Then, we have

1000X = 1023.562562562...............----------(1) 

No. of digits between the 2nd repeated pattern and decimal = 6

So, multiply the given decimal by 1000000. Then, we have

1000000X = 1023562.562562562...............----------(2)

(2) - (1) --------> 999000X = 1022538

X = 1022539 / 999000 

Hence, 1.023562562562.......... =  1022539 / 999000

In the above examples, all the non terminating decimals have been converted into fractions. Because all these  non terminating decimals have repeated patters. 

But, in "non recurring decimals", we will not have repeated pattern. Hence, we can not convert "non recurring decimals" into fractions. 

After having gone through the stuff and examples, we hope that the students would have understood, "non recurring decimals"

Related Topics

Converting percent into fractions

Converting improper fractions into mixed fractions

Converting mixed fractions into improper fractions

Converting decimals into fractions

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