Roberto wants to clean up his neighborhood by picking up trash. The total distance around his block is 1 3/4 of a mile. He decides to do this over a two-day period. If he walks 5/8 of a mile on the first day, how far does he need to walk the second day to pick up trash?
Roberto has already walked 5/8 of a mile and has 1 3/4 miles left to walk around the block.
He needs to walk 1 3/4 - 5/8 = 7/8 of a mile on the second day to pick up trash. Answer: \boxed{\frac{7}{8}}.