To add 2/3 and 3/4, we need to find a common denominator. The smallest common multiple of 3 and 4 is 12, so we can convert the fractions to have a denominator of 12:
2/3 = 8/12
3/4 = 9/12
Now we can add the two fractions:
8/12 + 9/12 = 17/12
The sum of 2/3 and 3/4 is 17/12. However, this fraction is an improper fraction, so we can simplify it by dividing the numerator and denominator by their greatest common factor, which is 1:
17/12 = 1 5/12
Therefore, the sum of 2/3 and 3/4, expressed as a fraction in lowest terms, is 1 5/12.