1)

[tex] - 1 \frac{7}{15} - 2 \frac{4}{5} = - 1 \frac{7}{15} - 2 \frac{12}{15} = - 3 \frac{19}{15} = - 4 \frac{4}{15} [/tex]

2)

[tex]3 \frac{1}{6 } - 5 \frac{3}{8} = 3 \frac{4}{24} - 5 \frac{9}{24} = - 2 \frac{5}{24} [/tex]

3)

[tex] - 2 \frac{5}{12} - ( - 3 \frac{3}{20} ) = - 2 \frac{25}{60} + 3 \frac{9}{60} = 2 \frac{69}{60} - 2 \frac{25}{60} = \frac{44}{60} = \frac{11}{15} [/tex]

4)

[tex]1.8 - 4 \frac{7}{15} =1 \frac{4}{5} - 4 \frac{7}{15} = 1 \frac{12}{15} - 4 \frac{7}{15} = 1 \frac{12}{15} - 3 \frac{22}{15} =\\= - 2 \frac{10}{15} = - 2 \frac{2}{3} [/tex]

5)

[tex] - 1 \frac{3}{20} + 3 \frac{7}{10} - 0.6 - \frac{2}{5} = - 1.15 + 3.7 - 0.6 - 0.4 = \\ = - 1.15 + 3.7 - 1 = 2.7 - 1.15 = 1.55[/tex]