XP Math - Forums - View Single Post - i dont knw how to write the decimals as comon fractoins in simplest form?
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11-30-2010   #9
Lisasmith111

Join Date: Nov 2010
Posts: 36

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