Odpowiedź :
[tex]3\frac{5}{7} - 2,1 + 1\frac{1}{5} = \frac{26}{7} - \frac{21}{10} + \frac{6}{5} = \frac{260}{70} -\frac{147}{70} + \frac{84}{70} = \frac{197}{70} = 2\frac{57}{70}[/tex]
[tex]3\frac{5}{7} - 2,1 + 1\frac{1}{5} = \frac{26}{7} - \frac{21}{10} + \frac{6}{5} = \frac{260}{70} -\frac{147}{70} + \frac{84}{70} = \frac{197}{70} = 2\frac{57}{70}[/tex]