Tham khảo
` a) 3+\frac{5}{9}=\frac{3.9+5}{9}=\frac{32}{9}`
`b) \frac{6}{20}+\frac{4}{5}=\frac{3}{10}+\frac{8}{10}=\frac{11}{10}`
`c) \frac{7}{91}-\frac{4}{92}=\frac{7.92-4.91}{91.92}=\frac{280}{8372}=\frac{10}{299}`
`d) \frac{30}{45}-\frac{2}{5}=\frac{30-2.9}{45}=\frac{12}{45}=\frac{4}{15}`
`e) \frac{12}{9}-\frac{1}{4}=\frac{12.4-9}{36}=\frac{39}{36}=\frac{13}{12}`
`f) \frac{7}{5}-\frac{2}{3}=\frac{7.3-5.2}{15}=\frac{11}{15}`
`i) 2-\frac{3}{2}=2-1,5=0,5`
`l) \frac{3}{4}+\frac{5}{9}=\frac{3.9+5.4}{36}=\frac{47}{36}`
`\text{©CBT}`