а) $$-1{,}6 - (-0{,}56) = -1{,}6 + 0{,}56 = -1{,}04$$
б) $$2{,}4 \times 1\frac{7}{8} = 2{,}4 \times \frac{15}{8} = \frac{24}{10} \times \frac{15}{8} = \frac{3}{5} \times \frac{15}{1} = \frac{45}{5} = 4{,}5$$
в) $$4\frac{7}{8} : 1\frac{6}{7} \times 16 = \frac{39}{8} : \frac{13}{7} \times 16 = \frac{39}{8} \times \frac{7}{13} \times 16 = \frac{3 \times 7}{1 \times 1} \times 2 = 21 \times 2 = 42$$
Ответ: