Question

Tính bằng cách thuận tiện nhất:

\(\frac{4}{5}\):\(\frac{2}{9}\)x\(\frac{2}{9}\):\(\frac{4}{5}\)

Answer 1

4/5 : 2/9 x 2/9 : 4/5
= 4/5 x 9/2 x 2/9 x 5/4
= ( 4/5 x 5/4 ) x ( 9/2 x 2/9 )
= 1x1
= 1

Answer 2

\(\frac{4}{5}:\frac{2}{9}\times\frac{2}{9}:\frac{4}{5}\)

\(=\frac{4}{5}\times\frac{9}{2}\times\frac{2}{9}\times\frac{5}{4}\)

\(=\left(\frac{4}{5}\times\frac{5}{4}\right)\times\left(\frac{2}{9}\times\frac{9}{2}\right)\)

\(=1\times1\)

\(=1\)