Well I don't know how to show work on this one.
50. 2 3/4 is between 2 and 3, three times farther from two than three. Draw a dot in approximately that locations and mark it 2 3/4.
51. 4 1/3 is between 4 and 5, twice as far from five as from four. Draw a dot and mark it 4 1/3.