(Дробь 3 7+ дробь 1/3): дробь 11 21

[latex] \frac{3}{7} [/latex]+[latex] \frac{1}{3} [/latex]=[latex] \frac{9+7}{21} [/latex]=[latex] \frac{16}{21} [/latex] [latex] \frac{16}{21} [/latex]:[latex] \frac{11}{21} [/latex]=[latex] \frac{16*21}{21*11} [/latex]=[latex] \frac{16}{11} [/latex]=1[latex] \frac{5}{11} [/latex]