Question

Tính giá trị biểu thức sau
a ) ( -4 + \(\dfrac{-2}{3}+1\dfrac{3}{4}\)).\(\dfrac{-12}{13}\)
b) \(\dfrac{-1}{2}+\dfrac{5}{6}-3,12+5,1\)
c) \(\left(\dfrac{4}{25}+\dfrac{7}{12}-\dfrac{9}{20}\right).2,5+0,25\)

Answer 1

a: \(=\left(\dfrac{-48}{12}+\dfrac{-8}{12}+\dfrac{21}{12}\right)\cdot\dfrac{-12}{13}\)

\(=\dfrac{-35}{12}\cdot\dfrac{-12}{13}=\dfrac{35}{13}\)

b: \(=\dfrac{-3}{6}+\dfrac{5}{6}-\dfrac{312}{100}+\dfrac{51}{10}\)

\(=\dfrac{1}{3}-\dfrac{312}{100}+\dfrac{51}{10}=\dfrac{347}{150}\)

c: \(=\left(\dfrac{48}{300}+\dfrac{175}{300}-\dfrac{135}{100}\right)\cdot\dfrac{5}{2}+\dfrac{1}{4}\)

\(=\dfrac{88}{300}\cdot\dfrac{5}{2}+\dfrac{1}{4}=\dfrac{59}{60}\)