Dưới đây là lời giải chi tiết cho các bài toán trong hình:

1) A = \((8 + 2 \cdot \frac{1}{3} \cdot \frac{3}{5}) - (5 + 0,4) - (3 - 2)\)
- \(2 \cdot \frac{1}{3} \cdot \frac{3}{5} = \frac{2 \cdot 1 \cdot 3}{3 \cdot 5} = \frac{6}{15} = \frac{2}{5}\)
- \(8 + \frac{2}{5} = 8,4\)
- \(5 + 0,4 = 5,4\)
- \(3 - 2 = 1\)
- \(A = 8,4 - 5,4 - 1 = 2\)

2) B = \(\left(\frac{7 - \frac{1}{2}}{3 \cdot \frac{4}{5}}\right) : \left(\frac{5 - \frac{1}{4}}{5 \cdot \frac{8}{5}}\right)\)
- \(7 - \frac{1}{2} = 7 - 0,5 = 6,5\)
- \(3 \cdot \frac{4}{5} = \frac{12}{5}\)
- \(\frac{6,5}{\frac{12}{5}} = 6,5 \cdot \frac{5}{12} = \frac{32,5}{12} = 2,7083\)
- \(5 - \frac{1}{4} = 5 - 0,25 = 4,75\)
- \(5 \cdot \frac{8}{5} = 8\)
- \(\frac{4,75}{8} = 0,59375\)
- \(B = \frac{2,7083}{0,59375} = 4,56\)

3) C = \((5,1 - 3,4) - (-3,4 + 5,1)\)
- \(5,1 - 3,4 = 1,7\)
- \(-3,4 + 5,1 = 1,7\)
- \(C = 1,7 - 1,7 = 0\)

4) D = \(\left(\frac{5}{7} + \frac{7}{9}\right) - \left(\frac{7}{9} + \frac{2}{7}\right)\)
- \(\frac{5}{7} + \frac{7}{9} = \frac{5 \cdot 9 + 7 \cdot 7}{7 \cdot 9} = \frac{45 + 49}{63} = \frac{94}{63}\)
- \(\frac{7}{9} + \frac{2}{7} = \frac{7 \cdot 7 + 2 \cdot 9}{9 \cdot 7} = \frac{49 + 18}{63} = \frac{67}{63}\)
- \(D = \frac{94}{63} - \frac{67}{63} = \frac{27}{63} = \frac{9}{21} = \frac{3}{7}\)

5) E = \(0,65 \cdot 78 + 2 \cdot \frac{1}{5} \cdot 2020 + 0,35 \cdot 78 - 2 \cdot 2 \cdot 2020\)
- \(0,65 \cdot 78 = 50,7\)
- \(2 \cdot \frac{1}{5} \cdot 2020 = 2 \cdot 404 = 808\)
- \(0,35 \cdot 78 = 27,3\)
- \(2 \cdot 2 \cdot 2020 = 8080\)
- \(E = 50,7 + 808 + 27,3 - 8080 = 886 - 8080 = -7194\)

6) F = \(\left[\left(\frac{1}{81} + \frac{3}{162}\right) : \left(\frac{81}{17} + \frac{35}{34}\right)\right] : \left[\left(\frac{9}{51} + \frac{7}{102}\right) : \left(\frac{102}{5} + 2017\right)\right]\)
- \(\frac{1}{81} + \frac{3}{162} = \frac{2}{81}\)
- \(\frac{81}{17} + \frac{35}{34} = \frac{162}{34} + \frac{35}{34} = \frac{197}{34}\)
- \(\left(\frac{2}{81}\right) : \left(\frac{197}{34}\right) = \frac{2}{81} \cdot \frac{34}{197} = \frac{68}{15957}\)
- \(\frac{9}{51} + \frac{7}{102} = \frac{18}{102} + \frac{7}{102} = \frac{25}{102}\)
- \(\frac{102}{5} + 2017 = 20,4 + 2017 = 2037,4\)
- \(\left(\frac{25}{102}\right) : \left(2037,4\right) = \frac{25}{102 \cdot 2037,4} = \frac{25}{208614,8}\)
- \(F = \frac{\frac{68}{15957}}{\frac{25}{208614,8}} = \frac{68 \cdot 208614,8}{15957 \cdot 25} = \frac{14185806,4}{398925} = 35,56\)

Lưu ý: Các phép tính trên có thể được làm tròn để dễ dàng tính toán.