Question

Tính bằng cách thuận tiện nhất, rồi viết kết quả dưới dạng số thập phân:

a/\(\frac{2}{3}.\frac{3}{4}.\frac{4}{5}\)

b/\(\frac{1}{2}:\frac{3}{4}:\frac{5}{6}\)

Help me!

Answer 1

a)2 phần 5

b)4 phần 5

Answer 2

\(\frac{2}{3}\times\frac{3}{4}\times\frac{4}{5}=\frac{2}{5}\)

\(\frac{1}{2}:\frac{3}{4}:\frac{5}{6}=\frac{1}{2}\times\frac{4}{3}\times\frac{6}{5}=\frac{1\times2\times2}{5}=\frac{4}{5}\)

Answer 3

\(\frac{2}{3}.\frac{3}{4}.\frac{4}{5}=\frac{2}{5}=\frac{4}{10}=0,4\)

\(\frac{1}{2}:\frac{3}{4}:\frac{5}{6}=\frac{1}{2}.\frac{4}{3}.\frac{6}{5}=\frac{4}{5}=\frac{8}{10}=0,8\)

Answer 4

a )\(\frac{2}{3}\cdot\frac{3}{4}\cdot\frac{4}{5}=\) \(\frac{2\cdot3\cdot4}{3\cdot4\cdot5}\)\(=\frac{2}{5}\)

b )  \(\frac{1}{2}:\frac{3}{4}:\frac{5}{6}\)\(=\frac{1\cdot4\cdot6}{2\cdot3\cdot5}\)\(=\frac{24}{30}=\frac{4}{5}\)

Answer 5

\(\frac{2}{3}\cdot\frac{3}{4}\cdot\frac{4}{5}=\frac{2\cdot3\cdot4}{3\cdot4\cdot5}=\frac{2}{5}\)

\(\frac{1}{2}\cdot\frac{3}{4}\cdot\frac{5}{6}=\frac{1\cdot4\cdot6}{2\cdot3\cdot5}=\frac{4}{5}\)