Question

$\frac{5}{7} +\frac{6}{9}$

Answer 1

приводим к общему знаменателю:

$\frac{5}{7}+\frac{6}{9} =\frac{5*9}{7*9} +\frac{6*7}{9*7}=\frac{45}{63}+\frac{42}{63}=\frac{45+42}{63}=\frac{87}{63} =1\frac{24}{63} =1\frac{8}{21}$