Question

tính = cách thuận tiện nhất :

a. 2\3 x 4\5 + 1\3 x 2\5                      b. 2\3 x 4\5 - 1\3 x 4\5 

Answer 1

\(a,\frac{2}{3}.\frac{4}{5}+\frac{1}{3}.\frac{2}{5}\)

= \(\frac{2}{5}.\frac{4}{3}+\frac{1}{3}.\frac{2}{5}=\frac{2}{5}\left(\frac{4}{3}+\frac{1}{3}\right)=\frac{2}{5}.\frac{5}{3}=\frac{2}{3}\)

Answer 2

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Answer 3

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

   \(=\frac{4}{5}\left(\frac{2}{3}-\frac{1}{3}\right)=\frac{4}{5}.\frac{1}{3}=\frac{4}{15}\)

L-I-K-E NHA

Answer 4

4/5x3/4+2/5x3/4-3/4x1/5