Question

Tính nhanh giá trị biểu thức sau :

B=\(\frac{2}{15}+\left(\frac{5}{9}+\frac{-6}{9}\right)\)

Answer 1

\(B=\frac{2}{15}+\left(\frac{5}{9}+\frac{-6}{9}\right)\)

\(\Leftrightarrow B=\frac{2}{15}+\frac{-1}{9}\)

\(\Leftrightarrow B=\frac{12}{90}+\frac{-10}{90}\)

\(\Leftrightarrow B=\frac{2}{90}\)

\(\Leftrightarrow B=\frac{1}{45}\)

Answer 2

\(B=\frac{2}{15}=\left(\frac{5}{9}+\frac{-6}{9}\right)\)

\(B=\frac{2}{15}+\frac{-1}{9}\)

\(B=\frac{18}{135}+\frac{-15}{135}\)

\(B=\frac{3}{135}\)

Answer 3

\(B=\frac{2}{15}+\left(\frac{5}{9}+-\frac{6}{9}\right)\)

\(B=\frac{2}{15}+-\frac{1}{9}\)

\(B=\frac{1}{45}\)

\(Linh\)\(Yukiko\)

Answer 4

\(B=\frac{2}{5}+(\frac{5}{9}+\frac{-6}{9})\)

\(=\frac{2}{15}+(\frac{5+\left(-6\right)}{9})\)

\(=\frac{2}{15}+\frac{-1}{9}=\frac{6}{45}+\frac{-5}{45}=\frac{6+\left(-5\right)}{45}\)

\(=\frac{1}{45}\)

Answer 5

Ta có B=2/15+(5/9+-6/9)

          B=2/15+-1/9

          B=6/45+ -5/45

         B=1/45

Answer 6

\(B=\frac{2}{15}+\left(\frac{5}{9}+\frac{-6}{9}\right)\)

\(B=\frac{2}{15}+\frac{-1}{9}\)

\(B=\frac{2.6+\left(-1\right).10}{90}\)

\(B=\frac{2}{90}=\frac{1}{45}\)