Question

[mai nguyễn]

bài 1: Tính giá trị biểu thức:
1) H= [0,(32) . 1,(5) - 0,(25)] . \(\dfrac{11}{83}\)
2) A= \(\dfrac{0,5+0,\left(3\right)-0,1\left(6\right)}{2,5+1,\left(6\right)-0,8\left(3\right)}\)

Answer 1

[Nguyễn Nam]

\(H=\left[0,\left(32\right).1,\left(5\right)-0,\left(25\right)\right].\dfrac{11}{83}\)

\(\Leftrightarrow H=\left(\dfrac{32}{99}.\dfrac{14}{9}-\dfrac{25}{99}\right).\dfrac{11}{83}\)

\(\Leftrightarrow H=\left(\dfrac{448}{891}-\dfrac{25}{99}\right).\dfrac{11}{83}\)

\(\Leftrightarrow H=\left(\dfrac{448}{891}-\dfrac{225}{891}\right).\dfrac{11}{83}\)

\(\Leftrightarrow H=\dfrac{448-225}{891}.\dfrac{11}{83}\)

\(\Leftrightarrow H=\dfrac{223}{891}.\dfrac{11}{83}\)

\(\Leftrightarrow H=\dfrac{2453}{73953}\)

\(\Leftrightarrow H=\dfrac{223}{6723}\)

2) \(A=\dfrac{0,5+0,\left(3\right)-0,1\left(6\right)}{2,5+1,\left(6\right)-0,8\left(3\right)}\)

\(\Leftrightarrow A=\dfrac{\dfrac{3}{6}+\dfrac{2}{6}-\dfrac{1}{6}}{\dfrac{15}{6}+\dfrac{10}{6}-\dfrac{5}{6}}\)

\(\Leftrightarrow A=\dfrac{\dfrac{3+2-1}{6}}{\dfrac{15+10-5}{6}}\)

\(\Leftrightarrow A=\dfrac{\dfrac{4}{6}}{\dfrac{20}{6}}\)

\(\Leftrightarrow A=\dfrac{4}{6}.\dfrac{6}{20}\)

\(\Leftrightarrow A=\dfrac{24}{120}\)

\(\Leftrightarrow A=\dfrac{1}{5}\)