Câu 3: Trang 50 sách VNEN toán lớp...

Cách làm:
1. $4+\frac{1}{4} = \frac{4}{1}+\frac{1}{4}=\frac{4}{4}+\frac{1}{4}=\frac{5}{4}$
2. $\frac{7}{6} -1 = \frac{7}{6}-\frac{1}{1}=\frac{7}{6}-\frac{6}{6}=\frac{1}{6}$
3. $7- \frac{8}{5}= \frac{7}{1}-\frac{8}{5}=\frac{35}{5}-\frac{8}{5}=\frac{27}{5}$
4. $\frac{3}{4}+5= \frac{3}{4}+\frac{5}{1}=\frac{3}{4}+\frac{20}{4}=\frac{23}{4}$

Câu trả lời:
1. $4+\frac{1}{4} = \frac{5}{4}$
2. $\frac{7}{6} -1 = \frac{1}{6}$
3. $7- \frac{8}{5}= \frac{27}{5}$
4. $\frac{3}{4}+5= \frac{23}{4}$