Решение:

Первый столбик:

1. $$\frac{4}{7} \cdot \frac{8}{21} = \frac{4 \cdot 8}{7 \cdot 21} = \frac{32}{147} = 0,(2176870748299319727891156462585)$$
2. $$\frac{14}{15} \cdot \frac{32}{147} = \frac{14 \cdot 32}{15 \cdot 147} = \frac{448}{2205} = \frac{64}{315} = 0,2031746031746031746031746031746$$
3. $$\frac{64}{315} + 2\frac{1}{3} = \frac{64}{315} + \frac{7}{3} = \frac{64}{315} + \frac{7 \cdot 105}{3 \cdot 105} = \frac{64}{315} + \frac{735}{315} = \frac{799}{315} = 2,5365079365079365079365079365079$$
4. $$\frac{799}{315} - 1\frac{4}{5} = \frac{799}{315} - \frac{9}{5} = \frac{799}{315} - \frac{9 \cdot 63}{5 \cdot 63} = \frac{799}{315} - \frac{567}{315} = \frac{232}{315} = 0,73650793650793650793650793650794$$

Второй столбик:

1. $$\frac{7}{27} : \frac{1}{9} = \frac{7}{27} \cdot \frac{9}{1} = \frac{7 \cdot 9}{27 \cdot 1} = \frac{63}{27} = \frac{7}{3} = 2,(3)$$
2. $$\frac{7}{3} \cdot \frac{51}{56} = \frac{7 \cdot 51}{3 \cdot 56} = \frac{357}{168} = \frac{17}{8} = 2,125$$
3. $$\frac{17}{8} + 2\frac{1}{6} = \frac{17}{8} + \frac{13}{6} = \frac{17 \cdot 3}{8 \cdot 3} + \frac{13 \cdot 4}{6 \cdot 4} = \frac{51}{24} + \frac{52}{24} = \frac{103}{24} = 4,291(6)$$
4. $$\frac{103}{24} - 1\frac{1}{3} = \frac{103}{24} - \frac{4}{3} = \frac{103}{24} - \frac{4 \cdot 8}{3 \cdot 8} = \frac{103}{24} - \frac{32}{24} = \frac{71}{24} = 2,958(3)$$