Приведите дробь:4/9 5/6 7/2 к знаменателю 187/8 5/16 21/40 к знаменателю 80

К знаменателю 18:
$\frac{4}{9} = \frac{4*2}{9*2} = \frac{8}{18}$

$\frac{5}{6} = \frac{5*3}{6*3} = \frac{15}{18}$

$\frac{7}{2} = \frac{7*9}{2*9} = \frac{63}{18}$

К знаменателю 80:

$\frac{7}{8} = \frac{7*10}{8*10} = \frac{70}{80}$

$\frac{5}{16} = \frac{5*5}{5*16} = \frac{25}{80}$

$\frac{21}{40} = \frac{21*2}{40*2} = \frac{42}{80}$