\(7\frac{1}{12}-4\frac{3}{4}+2\frac{1}{2}\)

= 5\(\left(\frac{1-9+6}{12}\right)\)
= 5\(\left(\frac{-2}{12}\right)\)
= 4\(\left(\frac{12-2}{12}\right)\)
(Carry one from 5 and call it 12)
 = \(4\frac{10}{12}\)
= 4\(\frac{5}{6}\)