Приведите дробь 1/4 кчислителю 3;5;7;9;10;13; приведите дробь 4/10 к знаменателю...

1)
$\frac{1}{4} = \frac{1*3}{4*3} = \frac{3}{12} \\ \\ \frac{1}{4} = \frac{1*5}{4*5} = \frac{5}{2} \\ \\ \frac{1}{4} = \frac{1*7}{4*7} = \frac{7}{28} \\ \\ \frac{1}{4} = \frac{1*9}{4*9} = \frac{9}{36} \\ \\ \frac{1}{4} = \frac{1*10}{4*10} = \frac{10}{40} \\ \\ \frac{1}{4} = \frac{1*13}{4*13} = \frac{13}{52}$

2)
$\frac{4}{10} = \frac{4:2}{10:2} = \frac{2}{5} \\ \\ \frac{4}{10} = \frac{4*2}{10*2} = \frac{8}{20} \\ \\ \frac{4}{10} = \frac{4*4}{10*4} = \frac{16}{40} \\ \\ \frac{4}{10} = \frac{2}{5} = \frac{2*3}{5*3} = \frac{6}{15} \\ \\ \frac{4}{10} = \frac{2}{5} = \frac{2*5}{5*5} = \frac{10}{25}$