$\frac{5}{11}$ + $\frac{1}{4}$ + $\frac{2}{5}$ + $\frac{6}{11}$ +$\frac{3}{4}$ + $\frac{6}{25}$ + $\frac{9}{25}$
= ( $\frac{5}{11}$ + $\frac{6}{11}$ ) + ( $\frac{1}{4}$ +$\frac{3}{4}$ ) + ( $\frac{6}{25}$ + $\frac{9}{25}$ + $\frac{2}{5}$ )
= $\frac{11}{11}$ + $\frac{4}{4}$ + $\frac{25}{25}$
= 1 + 1 + 1
= 3
CHÚC HỌC TỐT !