Question

Thực hiện phép tính:

a. \(\frac{2}{3}-\frac{5}{7}.\frac{14}{25}\)               b.\(\frac{-2}{5}.\frac{5}{8}+\frac{5}{8}.\frac{3}{5}\)              c.\(25\%-1\frac{1}{2}+0,5.\frac{12}{5}\)

 

Answer 1

a) \(\frac{2}{3}-\frac{5}{7}\cdot\frac{14}{25}\)

\(=\frac{2}{3}-\frac{2}{5}=\frac{4}{15}\)

b) \(\frac{-2}{5}\cdot\frac{5}{8}+\frac{5}{8}\cdot\frac{3}{5}\)

\(=\frac{5}{8}\left(-\frac{2}{5}+\frac{3}{5}\right)\)

\(=\frac{5}{8}\cdot\frac{1}{5}=\frac{1}{8}\)

c) \(25\%-1\frac{1}{2}+0,5\cdot\frac{12}{5}\)

\(=0,25-1,5+0,5\cdot2,4\)

\(=0,25-1,5+1,2=-0,05\)

Answer 2

a) \(\frac{2}{3}-\frac{5}{7}\cdot\frac{14}{25}=\frac{2}{3}-\frac{2}{5}=\frac{10-6}{15}=\frac{4}{15}\)

b) \(-\frac{2}{5}\cdot\frac{5}{8}+\frac{5}{8}\cdot\frac{3}{5}=\frac{5}{8}\cdot\left(-\frac{2}{5}+\frac{3}{5}\right)=\frac{5}{8}\cdot\frac{1}{5}=\frac{1}{8}\)

c) \(25\%-1\frac{1}{2}+0,5\cdot\frac{12}{5}=\frac{1}{4}-\frac{3}{2}+\frac{1}{2}\cdot\frac{12}{5}=\frac{1}{4}-\frac{3}{2}+\frac{6}{5}=\frac{5-30+24}{20}=-\frac{1}{20}\)

~~ Chúc bạn học tốt ~~

Answer 3

a,\(\frac{2}{3}-\frac{5}{7}.\frac{14}{25}=\frac{2}{3}-\frac{2}{5}\)

                              \(=\frac{4}{15}\)

b, \(\frac{-2}{5}.\frac{-5}{8}+\frac{5}{8}.\frac{3}{5}=\frac{1}{4}+\frac{3}{8}\)

                                           \(=\frac{5}{8}\)

c, \(25\%-1\frac{1}{2}+0,5.\frac{12}{5}=0,25-1,5+0,5.2,4\)

                                                    \(=0,25-1,5+1,2\)

                                                     \(=-0,05\)

Answer 4

SỬA : CÂU b,

 \(\frac{-2}{5}.\frac{5}{8}+\frac{5}{8}.\frac{3}{5}=\frac{5}{8}\left(\frac{-2}{5}+\frac{3}{5}\right)\)

                                    \(=\frac{5}{8}.\left(\frac{1}{5}\right)=\frac{1}{8}\)

Answer 5

mình sai mất câu B :v