Write the following infinite decimal expansion as a fraction. You do not need to simplify.

0.555...

1 answer

To convert the infinite decimal \( 0.555... \) into a fraction, we can let \( x \) represent the repeating decimal:

\[ x = 0.555... \]

Next, we can multiply both sides of the equation by 10 to shift the decimal point one place to the right:

\[ 10x = 5.555... \]

Now we have two equations:

  1. \( x = 0.555... \)
  2. \( 10x = 5.555... \)

Next, we can subtract the first equation from the second:

\[ 10x - x = 5.555... - 0.555... \]

This simplifies to:

\[ 9x = 5 \]

Now, we can solve for \( x \) by dividing both sides by 9:

\[ x = \frac{5}{9} \]

Thus, the fraction representation of the infinite decimal \( 0.555... \) is

\[ \frac{5}{9} \]