Question

Gía trị của biểu thức [ 4\(\frac{2}{5}\)+ 2\(\frac{3}{7}\)] + [ 5\(\frac{4}{7}\)- 2\(\frac{2}{5}\)]

Answer 1

\(=4\frac{2}{5}+2\frac{3}{7}+5\frac{4}{7}-2\frac{2}{5}\) 

\(=\frac{22}{5}+\frac{17}{7}+\frac{39}{7}-\frac{12}{5}\)

\(=\left(\frac{22}{5}-\frac{12}{5}\right)+\left(\frac{17}{7}+\frac{39}{7}\right)\)

\(=2+8\)

\(=10\)

Answer 2

\(4\frac{2}{5}+2\frac{3}{7}+5\frac{4}{7}-2\frac{2}{5}\)

\(=\left(4\frac{2}{5}-2\frac{2}{5}\right)+\left(5\frac{4}{7}+2\frac{3}{7}\right)\)

\(=2+8\)

\(=10\)

Answer 3

\(\left(4\frac{2}{5}+2\frac{3}{7}\right)+\left(5\frac{4}{7}-2\frac{2}{5}\right)\)

\(=\left(4\frac{2}{5}-2\frac{2}{5}\right)+\left(2\frac{3}{7}+5\frac{4}{7}\right)\)

\(=2+\left(2+5+\frac{3}{7}+\frac{4}{7}\right)\)

\(=2+8=10\)

Answer 4

\(\left[4\frac{2}{5}+2\frac{3}{7}\right]+\left[5\frac{4}{7}-2\frac{2}{5}\right]\)

\(=\left[\frac{22}{5}+\frac{17}{7}\right]+\left[\frac{39}{7}-\frac{12}{5}\right]\)

\(=\frac{22}{5}+\frac{17}{7}+\frac{39}{7}-\frac{12}{5}\)

\(=\frac{22}{5}-\frac{12}{5}+\frac{17}{7}+\frac{39}{7}\)

\(=2+8=10\)