A=\(\frac{1}{4}+\frac{1}{9}+\frac{1}{16}+...+\frac{1}{81}+\frac{1}{100}\)
A=\(\frac{1}{2}-\frac{1}{2}+\frac{1}{3}-\frac{1}{3}+\frac{1}{4}-\frac{1}{4}+...+\frac{1}{9}-\frac{1}{9}+\frac{1}{10}-\frac{1}{10}\)
A= 0
=> A>\(\frac{65}{132}\)
Bài 1: Tính
a, \(22\frac{1}{2}.\frac{7}{9}+50\%-1,25\)
b,1,4\(.\frac{15}{49}-\left(\frac{4}{5}+\frac{2}{3}\right):2\frac{1}{5}\)
c,\(125\%.\left(-\frac{1}{2}\right)^2:\left(1\frac{5}{6}-1,6\right)+2016^0\)
d,1,4 .\(\frac{15}{49}-\left(20\%+\frac{2}{3}\right):2\frac{1}{5}\)
đ,125%.\(\left(\frac{1}{2}\right)^2:\left(1\frac{5}{6}-1,5\right)+2016^0\)
Bài 2 Tìm x biết
a,\(\left|\frac{3}{4}.x-\frac{1}{2}\right|=\frac{1}{4}\)
b, \(\frac{5}{3}.x-\frac{2}{5}.x=\frac{19}{10}\)
c, \(\left|2.x-\frac{1}{3}\right|=\frac{2}{9}\)
d, x-30%.x=-1\(\frac{1}{5}\)
TÌM x:
a) \(\frac{1}{2}x-\left(x-\frac{2}{3}\right)=x+\frac{1}{3}\)
b) \(\frac{x-5}{x+3}=\frac{5}{6}\)
c) \(\left(2x-1\right)^2=16\)
bài 4.Tính Nhanh
a.\(\frac{5}{2}+1-\frac{3}{7}+\frac{2}{24}-\frac{8}{14}\)
b .\(-\frac{23}{4}+\frac{1}{2}+\frac{21}{4}-2\)
thực hiện phép tính
a, \(\frac{-5}{21}+\frac{2}{9}\)
b, \(\frac{-4}{21}-\frac{5}{12}\)
c,\(\frac{6}{-4}+\frac{1}{8}\)
d, \(\frac{-56}{77}-\frac{30}{66}\)
e,\(\frac{-3}{9}+\frac{5}{-3}\)
BT1; Tính
a,\(\frac{-5}{7}\)+\(\frac{2}{7}\)+\(\frac{4}{-9}\)+\(\frac{4}{9}\)
b,(\(\frac{1}{2}\):\(\frac{3}{4}\))2
c,\(\frac{1}{2}\)+\(\frac{3}{4}\)-(\(\frac{4}{5}\)+\(\frac{3}{4}\))
d,56:54+23.22-225:152
e,\(\frac{7}{23}\)+\(\frac{4}{17}\)-\(\frac{7}{23}\)+\(\frac{13}{17}\)
g,19\(\frac{1}{4}\).\(\frac{7}{12}\)-15\(\frac{1}{4}\).\(\frac{7}{12}\)
BT2; Tìm x,
a,\(\frac{1}{2}\)x-\(\frac{2}{5}\)=\(\frac{1}{5}\)
b,|22+4x|+12=36
c,25x+2=89
\(\frac{91}{1,4}\)+\(\frac{91}{4,7}\)+\(\frac{91}{7,10}\)+...+\(\frac{91}{88,99}\)
5\(\frac{1}{7}\)-(3\(\frac{2}{3}\)+4\(\frac{1}{7}\))
Mấy anh chị soái ca soái tỷ nào đi ngang làm ơn giúp em giải bài này với,em cảm ơn trước ạ :`3
BT2;Tìm x;
a,71+(26-3x):5=75
b,|x-12|=5
c,\(\frac{7}{8}\)+x=\(\frac{3}{5}\)
d,\(\frac{1}{2}\)x-\(\frac{2}{5}\)=\(\frac{1}{5}\)
Tìm các số nguyên x,y biết: \(\frac{x+1}{2}-\frac{3}{5}=\frac{1}{2y}\)( với y\(\ne\) 0)
