a)
[tex]2 \frac{6}{7} - 1 \frac{3}{4} + \frac{1}{4} = 2 \frac{24}{28} - 1 \frac{21}{28} + \frac{7}{28} = 1 \frac{3}{28} + \frac{7}{28} = 1 \frac{10}{28} = 1 \frac{5}{14} [/tex]
b)
[tex]( \frac{5}{8} - \frac{3}{20} ) \times \frac{20}{38} = ( \frac{25}{40} - \frac{6}{40} ) \times \frac{20}{38} = \frac{19}{40} \times \frac{20}{38} = \frac{1}{2} \times \frac{1}{2} = \frac{1}{4} [/tex]
c)
[tex]1 \frac{8}{12} + 4 \times \frac{6}{9} = 1\frac{8}{12} + \frac{24}{9} = 1 \frac{72}{108} + \frac{192}{108} = 1 \frac{264}{108} = 3 \frac{48}{108} = 3 \frac{12}{27} [/tex]
d)
[tex]3 \frac{1}{3} \div \frac{2}{3} = \frac{10}{3} \times \frac{3}{2} = 10 \times \frac{1}{2} = \frac{10}{2} = 5[/tex]
e)
[tex]1 \frac{7}{10} \times \frac{4}{34} = \frac{17}{10} \times \frac{4}{34} = \frac{1}{5} \times \frac{2}{2} = \frac{2}{10} = \frac{1}{5} [/tex]
f)
[tex](2 \frac{3}{7} + 1 \frac{4}{6} ) - (5 \frac{6}{10} - 4 \frac{3}{5} ) = (2 \frac{18}{42} + 1 \frac{32}{48} ) - (5 \frac{6}{10} - 4 \frac{6}{10} ) = 3 \frac{50}{48} - 1 = 2 \frac{50}{48} = 3 \frac{2}{48} = 3 \frac{1}{24} [/tex]
Myślę że pomogłem ;)