Помогите!!!! Плиииииз!!!! Заранее...

1) $\frac{1}{4} + \frac{4}{10} = \frac{5*1}{5*4} + \frac{2*3}{2*10} = \frac{5}{20} + \frac{6}{20} = \frac{11}{20}$

2) $\frac{3}{5} - \frac{1}{6} = \frac{6*3}{6*5} - \frac{5*1}{5*6} = \frac{18}{30} - \frac{5}{30} = \frac{13}{30}$

3) $\frac{7}{10} - \frac{2}{15} = \frac{3*7}{3*10} - \frac{2*2}{2*15} = \frac{21}{30} - \frac{4}{30} = \frac{17}{30}$

4) $\frac{5}{12} + \frac{3}{8} = \frac{2*5}{2*12} + \frac{3*3}{3*8} = \frac{10}{24} + \frac{9}{24} = \frac{19}{24}$