i dont knw how to write the decimals as comon fractoins in simplest form? - XP Math - Forums

 XP Math - Forums i dont knw how to write the decimals as comon fractoins in simplest form?

 09-15-2010 #1 coolj999     Join Date: Sep 2010 Posts: 3 i dont knw how to write the decimals as comon fractoins in simplest form? :conf used::icon_c rying::icon _crying:
09-16-2010   #2
MAS1

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Quote:
 Originally Posted by coolj999 :conf used::icon_c rying::icon _crying:
Here are a couple of examples for terminating decimals:

1. 0.465
Look at a non-zero digit which is in the smallest place. In this case it is the 5 in the thousandths place. This means the denominator for your fraction will be 1000. Now write the digits "465" in the numerator. You should have:
465/1000 which is four hundred sixty five thousandths.
Now see if you can simplify the fraction. 5 is a factor of both the numerator and denominator so divide both by 5 giving
93/200

2. 2.76
Ignore the whole number part for now.
0.76 = 76/100 = 38/50 = 19/25
Now add the whole number part back in creating the mixed number 2 19/25

To find the fraction for non-terminating, repeating decimals:

1. 0.33333...
Let x = 3.33333...
then 10x = 3.33333...
10x - x = 3.3333... - 0.3333...
9x = 3 (All of the 3's to the right of the decimal place cancel out)
x = 3/9 = 1/3

2. 0.166666...
Let x = 0.166666...
10x = 1.66666...
10x - x = 1.66666... - 0.1666666...
9x = 1.5
18x = 3
x = 3/18 = 1/6

3. 0.142857142857142857...
x = 0.142857142857142857...
1000000x = 142857.142857142857142857...
1000000x - x = 142857
999999x = 142857
x = 142857/999999 = 15873/111111 = 5291/37037 = 1/7

Hope this helps!

 09-17-2010 #3 Mr. Hui Last Achievements     Join Date: Mar 2005 Posts: 10,650 I wonder what happens when you try to simplify 0.999... ? __________________ Do Math and you can do Anything!
 09-22-2010 #4 meetballs Last Achievements     Join Date: Mar 2010 Posts: 46 1/7 is the Answer
10-23-2010   #5
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Quote:
 Originally Posted by meetballs 1/7 is the Answer
Ummm, no.

 10-23-2010 #6 sugarmama Last Achievements     Join Date: Oct 2010 Posts: 4 hi Why don't u just ask ur teacher
11-29-2010   #7
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11-30-2010   #8
tiger190
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Quote:
 Originally Posted by MAS1 Here are a couple of examples for terminating decimals: 1. 0.465 Look at a non-zero digit which is in the smallest place. In this case it is the 5 in the thousandths place. This means the denominator for your fraction will be 1000. Now write the digits "465" in the numerator. You should have: 465/1000 which is four hundred sixty five thousandths. Now see if you can simplify the fraction. 5 is a factor of both the numerator and denominator so divide both by 5 giving 93/200 2. 2.76 Ignore the whole number part for now. 0.76 = 76/100 = 38/50 = 19/25 Now add the whole number part back in creating the mixed number 2 19/25 To find the fraction for non-terminating, repeating decimals: 1. 0.33333... Let x = 3.33333... then 10x = 3.33333... 10x - x = 3.3333... - 0.3333... 9x = 3 (All of the 3's to the right of the decimal place cancel out) x = 3/9 = 1/3 2. 0.166666... Let x = 0.166666... 10x = 1.66666... 10x - x = 1.66666... - 0.1666666... 9x = 1.5 18x = 3 x = 3/18 = 1/6 3. 0.142857142857142857... x = 0.142857142857142857... 1000000x = 142857.142857142857142857... 1000000x - x = 142857 999999x = 142857 x = 142857/999999 = 15873/111111 = 5291/37037 = 1/7 Hope this helps!
omg wow you are one smart cookie

11-30-2010   #9
Lisasmith111
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Quote:
 Originally Posted by MAS1 Here are a couple of examples for terminating decimals: 1. 0.465 Look at a non-zero digit which is in the smallest place. In this case it is the 5 in the thousandths place. This means the denominator for your fraction will be 1000. Now write the digits "465" in the numerator. You should have: 465/1000 which is four hundred sixty five thousandths. Now see if you can simplify the fraction. 5 is a factor of both the numerator and denominator so divide both by 5 giving 93/200 2. 2.76 Ignore the whole number part for now. 0.76 = 76/100 = 38/50 = 19/25 Now add the whole number part back in creating the mixed number 2 19/25 To find the fraction for non-terminating, repeating decimals: 1. 0.33333... Let x = 3.33333... then 10x = 3.33333... 10x - x = 3.3333... - 0.3333... 9x = 3 (All of the 3's to the right of the decimal place cancel out) x = 3/9 = 1/3 2. 0.166666... Let x = 0.166666... 10x = 1.66666... 10x - x = 1.66666... - 0.1666666... 9x = 1.5 18x = 3 x = 3/18 = 1/6 3. 0.142857142857142857... x = 0.142857142857142857... 1000000x = 142857.142857142857142857... 1000000x - x = 142857 999999x = 142857 x = 142857/999999 = 15873/111111 = 5291/37037 = 1/7 Hope this helps!
That is a very useful post - I looked at a book on Engineering maths and did not understand how to do terminating decimals as fractions. However, your approach is nice, simple and direct. Thanks

 11-30-2010 #10 macincheese Last Achievements     Join Date: Nov 2010 Posts: 4 wooooowwwww u would... in a go way

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