Question

Tính nhanh :

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

Answer 1

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

= \(1-1+\dfrac{7}{12}\)

=\(\dfrac{1}{72}\)

Answer 2

A = ( 1/3+3/5+1/15)-(3/4+2/9+1/36)+1/72

= 1-1+1/72

= 1/72

Answer 3

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