Final answer:
To add 439 and four-fifths, convert four-fifths to an improper fraction and find a common denominator. Then, add the numerators.
Step-by-step explanation:
To add 439 and four-fifths, we first convert the mixed number four-fifths to an improper fraction. We multiply the denominator (5) by the whole number (4) and add the numerator (1) to get 21. So, four-fifths as an improper fraction is 21/5. Now we can add 439 and 21/5. To do this, we find a common denominator, which is 5, and then add the numerators. 439 + 21/5 is equal to 2194/5.