# how do you change a decimal into a fraction?!

• Jun 13th 2005, 03:16 PM
elmer7049
how do you change a decimal into a fraction?!
1.411411141144 -- how would you make this a fraction???
• Jun 13th 2005, 03:31 PM
Math Help
$\displaystyle 1.411411141144= 1 + \frac{411411141144}{1000000000000}$

or

$\displaystyle \frac{1411411141144}{1000000000000}$

or where you looking for something more elegant in a form similar to $\displaystyle \frac{223}{31}$?
• Jun 13th 2005, 03:34 PM
elmer7049
Ahhhhh
WOWWW!
thankyou soo muchh.... wow you're a lifesaver*
• Jun 13th 2005, 03:44 PM
Math Help
by the way $\displaystyle 223/31$ is not the correct answer. I was only asking if you wanted something similar?

By the way do you mean

1.411411411 where 411 is always repeating or did you mean precisely 1.411411141144 as you wrote

if you meant 1.411411411 then the answer is $\displaystyle 1+\frac{137}{333}$
• Jun 22nd 2005, 10:54 PM
beepnoodle
Yup, .411411 repeating forever is 411/999 which is 137/333. Notice that this works with every repeating decimal, just divide by a string of 9's of the same length as the repeating block. I found this out using a geometric series one day in proofs. Now it makes sense that any decimal with a repeating block is a rational number.
• Jan 5th 2006, 10:00 PM
earboth
hallo,

in addition try this more mechanical way to change repeating decimals into fractions:

Example: Transform .45123123123... into a fraction:
1. $\displaystyle x=0.45123\overline{123}$
2. Multiply x by a power of 10, so that you get instantly repeating decimals:
$\displaystyle 100\cdot x=45.123\overline{123}$
3. Multiply 100x with a power of 10, so that the first block of the repeating digits is before the point:
$\displaystyle 100 \cdot x \cdot 1000 = 45123.123 \overline{123}$
4. Now substract:
$\displaystyle 100 \cdot x \cdot 1000 = 45123.123 \overline{123}$
$\displaystyle 100\cdot x=45.123\overline{123}$
You'll get:
$\displaystyle 99900\cdot x= 45078$
$\displaystyle x=\frac{45078}{99900}$
Afterwards you may simplify this fraction – if it is possible!
$\displaystyle x=\frac{45078}{99900}=\frac{7513}{16650}$