Katya and Alec completed these steps to find the sum of Three and five-sixths and . Katya's work. 3 and 5-sixths plus 1-fourth. 3 StartFraction 5 times 2 over 12 EndFraction plus StartFraction 1 times 3 over 12 EndFraction. 3 and 10-twelfths plus 3-twelfths. 3 and 13-twelfths. 4 and 1-half. Alec's work. 3 and 5-sixths plus 1-fourth. 3 StartFraction 5 plus 4 over 10 EndFraction plus StartFraction 1 plus 6 over 10 EndFraction. 3 and 9-tenths plus 7-tenths. 3 and 16-tenths. 4 and 6-tenths. Which best describes the correct sum? Katya is correct because 12 is the only common denominator that can be used to find this sum. Katya is correct because Ten-twelfths is equivalent to Five-sixths and Three-twelfths is equivalent to One-fourth. Alec is correct because the common denominator is the sum of 6 and 4. Alec is correct because Nine-tenths is equivalent to and is equivalent to Seven-tenths.