\(\left(\dfrac{-5}{24}+0,75+\dfrac{7}{12}\right):\left(-2\dfrac{1}{8}\right)\)
=\(\left(\dfrac{-5}{24}+\dfrac{3}{4}+\dfrac{7}{12}\right):\left(\dfrac{-17}{8}\right)\) =\(\left(\dfrac{-5}{24}+\dfrac{18}{24}+\dfrac{14}{24}\right):\left(\dfrac{-17}{8}\right)\) = \(1.\dfrac{-8}{17}=\dfrac{-8}{17}\)Tìm x biết:\(\left(12\dfrac{7}{8}-10\dfrac{13}{18}\right):x-1\dfrac{7}{33}:\dfrac{8}{11}=1\dfrac{2}{3}\)
Tìm số nguyên \(x\):
a, \(\left(\dfrac{1}{12}+3\dfrac{1}{6}-30,75\right).x-8=\left(\dfrac{3}{5}+0,415\right)\)
b, \(4\dfrac{1}{3}.\left(\dfrac{1}{6}-\dfrac{1}{2}\right)\le x\le\dfrac{2}{3}.\left(\dfrac{1}{3}-\dfrac{1}{2}-\dfrac{3}{4}\right)\)
Tính một cách hợp lí :
a) \(4\dfrac{3}{4}+\left(-0.37\right)+\dfrac{1}{8}+\left(-1,28\right)+\left(-2,5\right)+3\dfrac{1}{12}\)
b) \(\dfrac{3}{5.7}+\dfrac{3}{7.9}+...+\dfrac{3}{59.61}\)
c) \(\dfrac{\dfrac{5}{22}+\dfrac{3}{13}-\dfrac{1}{2}}{\dfrac{4}{13}-\dfrac{2}{11}+\dfrac{3}{2}}\)
Tính giá trị của biểu thức sau :
\(A=8\dfrac{2}{7}-\left(3\dfrac{4}{9}+4\dfrac{2}{7}\right)\)
\(B=\left(10\dfrac{2}{9}+2\dfrac{3}{5}\right)-6\dfrac{2}{9}\)
D=\(\left(1-\dfrac{1}{2}\right)\left(1-\dfrac{1}{3}\right)\left(1-\dfrac{1}{4}\right)...\left(1-\dfrac{1}{2005}\right)\)
E=\(\dfrac{1^2}{1.3}.\dfrac{2^2}{2.4}.\dfrac{3^2}{3.5}....\dfrac{999^2}{999.1000}.\dfrac{1000^2}{1000.1001}\)
Tính một cách hợp lí
a. \(8\dfrac{5}{7}+3,15+1\dfrac{2}{7}+4,35\)
b. \(\left(4\dfrac{5}{23}-2\dfrac{2}{5}+7\dfrac{7}{13}\right)-\left(3\dfrac{5}{23}-6\dfrac{6}{13}\right)\)
c. \(-15\dfrac{1}{2}\times20,8+3,5\times9,5-15,5\times9,2+3\dfrac{1}{2}\times20\dfrac{1}{2}\)
giúp mk với , mai mk phải nộp bài rồi
cảm ơn các bn trước nha
Tìm \(x\), biết :
a) \(0,5x-\dfrac{2}{3}x=\dfrac{7}{12}\) b) \(x:4\dfrac{1}{3}=-2,5\)
c) \(5,5x=\dfrac{13}{15}\) d) \(\left(\dfrac{3x}{7}+1\right):\left(-4\right)=\dfrac{-1}{28}\)
Điền số thích hợp vào chỗ trống :
a) \(4\dfrac{2}{5}:2=\dfrac{....}{5}.\dfrac{1}{....}=\dfrac{....}{....}=.....\)
b) \(4\dfrac{2}{5}:2=\left(4+\dfrac{2}{5}\right):2=.....+\dfrac{....}{....}=.....\)
x-\(\dfrac{20}{11.13}-\dfrac{20}{13.15}-\dfrac{20}{15.17}-...-\dfrac{20}{53.55}=\dfrac{3}{11}\)
A=\(\dfrac{1}{1.2}+\dfrac{1}{2.3}+...+\dfrac{1}{99.100}\)
\(\dfrac{-2}{3}\left|x\right|+1\dfrac{1}{2}=\dfrac{2}{5}\)