Bài 1: Rút gọn rồi tính :
a) \(\frac{2}{5}+\frac{9}{15}\) b) \(\frac{15}{45}+\frac{25}{30}\) c) \(\frac{28}{32}+\frac{45}{72}\) d) \(\frac{4}{8}+\frac{8}{24}\)
Bài 3 : Tính :
a) \(\frac{2}{5}+\frac{2}{3}+\frac{3}{4}\) b) \(\frac{1}{3}+\frac{5}{12}+\frac{5}{6}\) c) \(\frac{1}{6}+\frac{5}{24}+\frac{2}{3}\)