If we take 0.408 and convert it to fraction, then we have:
408/1,000 because we have three places after the dot or period.
But that result would be 3.408 but not forever.
For doing it forever, we will replace a nine in the denominator of the fraction for every decimal place we have, this way:
0.408 forever = 408/999 (three decimal places) and now we add the 3.
So, we have 3 408/999
The answer is 3 408/999