Question

Tính nhanh:

A = \(\frac{1}{3}-\frac{3}{4}-\frac{-3}{5}+\frac{1}{72}-\frac{2}{9}-\frac{1}{36}+\frac{1}{15}\)

 

Answer 1

Ta có: \(A=\frac{1}{3}-\frac{3}{4}-\frac{-3}{5}+\frac{1}{72}-\frac{2}{9}-\frac{1}{36}+\frac{1}{15}\)

\(\Rightarrow A=\left(\frac{1}{3}-\frac{-3}{5}+\frac{1}{15}\right)-\left(\frac{3}{4}+\frac{2}{9}+\frac{1}{36}\right)+\frac{1}{72}\)

\(\Rightarrow A=\left(\frac{5}{15}+\frac{9}{15}+\frac{1}{15}\right)-\left(\frac{54}{72}+\frac{16}{72}+\frac{2}{72}\right)+\frac{1}{72}\)

\(\Rightarrow A=1-1+\frac{1}{72}\)

\(\Rightarrow A=\frac{1}{72}\)

Vậy \(A=\frac{1}{72}\)

Answer 2

A = \(\frac{1}{72}\)