Câu 1 : a , ( $\frac{4}{5}$ + $\frac{1}{2}$ ) × ( $\frac{3}{13}$ – $\frac{8}{13}$ ) b, Question Diễm Thu Câu 1 : a , ( $\frac{4}{5}$ + $\frac{1}{2}$ ) × ( $\frac{3}{13}$ - $\frac{8}{13}$ ) b, 5 years