Final answer:
The sum of three-sixths plus one-sixth in lowest terms is three-sixths.
Step-by-step explanation:
To find the sum of three-sixths plus one-sixth in lowest terms, we need to add the two fractions together. First, we need to find a common denominator, which in this case is 6. So three-sixths can be written as one-half and one-sixth can be written as one-sixth. Adding these fractions gives us one-half plus one-sixth, which is equal to three-sixths. Therefore, the sum of three-sixths plus one-sixth is equal to three-sixths.