Question

Tinh:

4/5-7/8

9/15+50/12

89/4.7/78

8/9:2/12

 

Answer 1

Lời giải:

$\frac{4}{5}-\frac{7}{8}=\frac{4\times 8-7\times 5}{5\times 8}=\frac{-3}{40}$ (bạn xem lại đề, lớp 4 chưa học số âm) 

$\frac{9}{15}+\frac{50}{12}=\frac{3}{5}+\frac{25}{6}=\frac{3\times 6+25\times 5}{5\times 6}=\frac{143}{30}$

$\frac{89}{4}\times \frac{7}{78}=\frac{623}{312}$

$\frac{8}{9}: \frac{2}{12}=\frac{8}{9}:\frac{1}{6}=\frac{8}{9}\times 6=\frac{16}{3}$