Question

Tính giá trị biểu thức: A=29\(\dfrac{1}{2}\)\(\times\)\(\dfrac{2}{3}\)+39\(\dfrac{1}{3}\)\(\times\)\(\dfrac{3}{4}\)+\(\dfrac{5}{6}\)
(Nhớ rút gọn đến tối giản, trình bày theo cách của học sinh lớp 5)

Answer 1

\(A=29\dfrac{1}{2}\cdot\dfrac{2}{3}+39\dfrac{1}{3}\cdot\dfrac{3}{4}+\dfrac{5}{6}\)

\(=\dfrac{59}{2}\cdot\dfrac{2}{3}+\dfrac{118}{3}\cdot\dfrac{3}{4}+\dfrac{5}{6}\)

\(=\dfrac{59}{3}+\dfrac{118}{4}+\dfrac{5}{6}\)

\(=\dfrac{59}{3}+\dfrac{59}{2}+\dfrac{5}{6}\)

\(=59\cdot\left(\dfrac{1}{3}+\dfrac{1}{2}\right)+\left(\dfrac{1}{3}+\dfrac{1}{2}\right)\)

\(=\dfrac{5}{6}\cdot\left(59+1\right)=\dfrac{5}{6}\cdot60=50\)