Question

Tính giá trị của biểu thức

A= \(\dfrac{12}{25}\)-\(\dfrac{4}{11}\)+\(\dfrac{13}{25}\)+\(1\dfrac{4}{9}\)-\(\dfrac{7}{11}\)

Sử dụng biện pháp tính nhanh để làm bài

Answer 1

\(A=\dfrac{12}{25}-\dfrac{4}{11}+\dfrac{13}{25}+1\dfrac{4}{9}-\dfrac{7}{11}\)

\(A=\dfrac{12}{25}+\dfrac{13}{25}-\dfrac{4}{11}-\dfrac{7}{11}+1\dfrac{4}{9}\)

\(A=\dfrac{12+15}{25}-\dfrac{4-7}{11}+\dfrac{13}{9}\)

\(A=\dfrac{25}{25}+\dfrac{3}{11}+\dfrac{13}{9}\)

\(A=1+\dfrac{3}{11}+\dfrac{13}{9}\)

\(A=\dfrac{11+3}{11}+\dfrac{13}{9}=\dfrac{14}{11}+\dfrac{13}{9}\)

\(A=\dfrac{126+141}{99}=\dfrac{42+47}{22}=\dfrac{89}{22}\)

\(=4\dfrac{1}{22}\)