1/3-1/9; 10/21-1/3;14/15-3/5;17/18-1/9;4/9-13/45;1/3-7/30

1) $\frac{1}{3} - \frac{1}{9} = \frac{3}{9} - \frac{1}{9} = \frac{2}{9}$

2) $\frac{10}{21} - \frac{1}{3} = \frac{10}{21} - \frac{7}{21} = \frac{3}{21}$

3) $\frac{14}{15} - \frac{3}{5} = \frac{14}{15} - \frac{9}{15} = \frac{5}{15}$

4) $\frac{17}{18} - \frac{1}{9} = \frac{17}{18} - \frac{2}{18} = \frac{15}{18}$

5) $\frac{4}{9} - \frac{13}{45} = \frac{20}{45} - \frac{13}{45} = \frac{7}{45}$

6) $\frac{1}{3} - \frac{7}{30} = \frac{10}{30} - \frac{7}{30} = \frac{3}{30} = 0,1$

НОЗ: 9, 21, 15, 18, 45, 30.