The following image was made from Add with Lines Designer:
You will notice that the addends 3/8 and 1/3 have unlike denominators. You must first rename 3/8 and 1/3 with a like or common denominator(LCD). The program COMPARE FRACTIONS shows how to find the LCD. In this case, each addend is written with a common denominator 24.
Once each addend is written with like denominators, the numerators may be added for the sum numerator.
The program ADD FRACTIONS - EASY shows how to add fractions with like denominators.
Written out, the example would look like this: