$4\frac{7}{12} - 1\frac{5}{12} + 2\frac{11}{12} = (4 - 1 + 2) + (\frac{7}{12} - \frac{5}{12} + \frac{11}{12}) = 5 + \frac{13}{12} = 5\frac{13}{12} = 6\frac{1}{12}$

$6\frac{14}{15} - 3\frac{2}{15} - 1\frac{7}{15} = (6 - 3 - 1) + (\frac{14}{15} - \frac{2}{15} - \frac{7}{15}) = 2 + \frac{5}{15} = 2\frac{5}{15}$