Tính:
a) 4 + 5/7 = ...........................
5/9 x 6/7 = ........................
3 - 7/5 = ............................
3/5 x 4/8 = ........................
b) 2 - 1/4 = ...........................
4 : 5/9 = ...........................
2/9 x 3/5 = .......................
3/8 : 4 = ...........................
a) 4 + 5/7 = .... 28/7 + 5/7=.33/7..............
5/9 x 6/7 = ..10/21....
3 - 7/5 = 15/5 - 7/5...8/5........
3/5 x 4/8 = ..3/10....
b) 2 - 1/4 = .8/4 - 1/4...7/4...
4 : 5/9 = ..4 x 9/5 = 36/5....
2/9 x 3/5 = .....2/15.....
3/8 : 4 = ......3/8 x 1/4 = 3/2.....
a) \(4+\dfrac{5}{7}=\dfrac{4}{1}+\dfrac{5}{7}=\dfrac{28}{7}+\dfrac{5}{7}=\dfrac{33}{7}\)
\(\dfrac{5}{9}\times\dfrac{6}{7}=\dfrac{10}{21}\)
\(3-\dfrac{7}{5}=\dfrac{3}{1}-\dfrac{7}{5}=\dfrac{15}{5}-\dfrac{7}{5}=\dfrac{8}{5}\)
\(\dfrac{3}{5}\times\dfrac{4}{8}=\dfrac{12}{40}=\dfrac{3}{10}\)
b) \(2-\dfrac{1}{4}=\dfrac{2}{1}-\dfrac{1}{4}=\dfrac{8}{4}-\dfrac{1}{4}=\dfrac{7}{4}\)
\(4:\dfrac{5}{9}=\dfrac{4}{1}:\dfrac{5}{9}=\dfrac{4}{1}\times\dfrac{9}{5}=\dfrac{36}{5}\)
\(\dfrac{2}{9}\times\dfrac{3}{5}=\dfrac{6}{45}=\dfrac{2}{15}\)
\(\dfrac{3}{8}:4=\dfrac{3}{8}:\dfrac{4}{1}=\dfrac{3}{8}\times\dfrac{1}{4}=\dfrac{3}{2}\)
