d. \( \frac{7}{8}+\frac{3}{5}= \)

To add the fractions \( \frac{7}{8} \) and \( \frac{3}{5} \), you first need to find a common denominator. The least common multiple of 8 and 5 is 40. So, convert each fraction: \( \frac{7}{8} = \frac{35}{40} \) and \( \frac{3}{5} = \frac{24}{40} \). Add them together: \( \frac{35}{40} + \frac{24}{40} = \frac{59}{40} \), which can also be expressed as \( 1 \frac{19}{40} \)! If you're ever in doubt about finding a common denominator, just remember: it’s like hosting a party! You want everyone (the fractions) to have the same size plate (denominator) to enjoy the meal (addition) together. And, while you may think these types of additions are foolproof, a common mistake is forgetting to simplify your final answer. Always double-check to see if there's a simpler form or if you can express it as a mixed number!