Ответ:\(\frac{9}{16}+\frac{3}{16}=\frac{12}{16}=\frac34\).\(12\frac{43}{56}-7\frac{22}{56}=5\frac{21}{56}=5\frac38\).Ответ: а) \(\frac34\); б) \(5\frac38\).