4/25 : ( 12/25 - 4/15 ) + 15/16 × 4/15

Решите задачу:

$1) \frac{12}{25} - \frac{4}{15} = \frac{12*3}{25*3} - \frac{4*5}{15*5} = \frac{36}{75} - \frac{20}{75} = \frac{36-20}{75} = \frac{16}{75}$
$2) \frac{4}{45} : \frac{16}{75} = \frac{4*75}{45*16} = \frac{300}{720} = \frac{5}{12}$
$3) \frac{15}{16} * \frac{4}{15} = \frac{15*4}{16*15} = \frac{60}{240} = \frac{1}{4}$
$4) \frac{5}{12} + \frac{1}{4} = \frac{5}{12} + \frac{1*3}{4*3} = \frac{5}{12} + \frac{3}{12} = \frac{8}{12} = \frac{2}{3}$