Webmath.com: Doing math with fractionsHere's how to convert .999999 to a fraction...

The decimal part of your number seems to have the repeating digit 9 in it.

Your original number to convert is 0.999999. Let's slide the decimal point in this number to the right 1 place(s) (the same number of digits in the number 9).

If we do this, we'll get a 9.999990 (slide the decimal in the 0.999999 right 1 places, you'll get 9.999990).

So what? Well now, we have two numbers with the same repeating decimal parts, 9.999990 and 0.999999.

Now let's just work a little algebra into all of this. Let's call your original number x. And in this case, x=0.999999. The number with the decimal point slid over can be called 10x, because 10x=9.999990

What if we subtracted these two equations (that is, subtract the items on the left of the equal sign
from the stuff on the right of the equal sign)?

`10x = 9.99999- x = 0.999999-------------9x = 8.99999.`

Now here's the important result of doing all of this: Notice how all of the repeating decimal parts have subtracted away to zero! We are left with a nice, simple 9 on the right side of the equal sign.

Now, solving 9x=9 for x by dividing both sides of it by 9, we'll get that x=9/9. And this is your answer.

How is this your answer? Well remember that above, x was originally set equal to 0.999999 via x=0.999999, and now we have that x is also equal to 9/9, so that means 0.999999=9/9..and there's 0.999999 written as a fraction!

This fraction,
can be reduced further to 1, because anything over itself(other than zero) is 1.
The fraction 1 is not reduced to lowest terms. We can reduce this fraction to lowest
terms by dividing both the numerator and denominator by 9.

Why divide by 9? 9 is the Greatest Common Divisor (GCD)
or Greatest Common Factor (GCF) of the numbers 0 and 9.
So, this fraction reduced to lowest terms is 1

So your final answer is: 0.999999 can be written as the fraction 1