[tex]a) 1\frac{5}{12} -\frac{9}{8} -2\frac{5}{6} = \frac{17}{12} -\frac{9}{8} -\frac{17}{6} =\frac{17}{12} -\frac{9}{8} -\frac{34}{12} =-\frac{17}{12} -\frac{9}{8} =-\frac{34}{24} -\frac{27}{24} =-\frac{61}{24} \\\\b)6\frac{3}{4} -2\frac{2}{3} -3\frac{1}{6} =\frac{27}{4} -\frac{8}{3} -\frac{29}{6} =\frac{27}{4} -\frac{16}{6} -\frac{29}{6} =\frac{27}{4} -\frac{45}{6} =\frac{81}{12} -\frac{90}{12} =-\frac{9}{12} =-\frac{3}{4}[/tex]
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