7.Giá trị biểu thức A=\(\frac{2008+\frac{2007}{2}+\frac{2006}{3}+\frac{2005}{4}+...+\frac{2}{2007}+\frac{1}{2008}}{\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+\frac{1}{5}+...+\frac{1}{2008}+\frac{1}{2009}}\)  là A=.................

a,A=1-2+3+4-5-6+7+8-9-...+2007+2008-2009-2010

b, \(\frac{1}{5^2}-\frac{1}{5^3}+\frac{1}{5^4}-\frac{1}{5^5}+..-\frac{1}{5^{101}}\).CM<\(\frac{1}{30}\)

Tính

a)  \(\frac{1}{5}+\frac{-1}{6}+\frac{1}{7}+\frac{1}{-8}+\frac{1}{9}+\frac{1}{8}+\frac{1}{-7}+\frac{-1}{6}+\frac{-1}{5}\)

b) (-11).36-64.11

c) \(\frac{\frac{1}{3}+\frac{1}{7}+\frac{1}{13}}{\frac{2}{3}+\frac{2}{7}+\frac{2}{13}}.\frac{\frac{3}{4}+\frac{3}{16}+\frac{3}{64}+\frac{3}{256}}{1+\frac{1}{4}+\frac{1}{16}+\frac{1}{64}}+\frac{3}{8}\)

So sánh

A=\(\frac{2006}{2007}-\frac{2007}{2008}+\frac{2008}{2009}-\frac{2009}{2010}\)

B=\(-\frac{1}{2006.2007}-\frac{1}{2008.2009}\)

So sánh

B=\(-\frac{1}{2011}-\frac{7}{11^2}-\frac{5}{11^3}-\frac{3}{11^4}\)

A=\(-\frac{1}{2011}-\frac{3}{11^2}-\frac{5}{11^4}\)

Tính

A=1-2+3+4-5-6+7+8-9-.....+2007+2008-2009-2010

B=2^2005-2^2003-2^2001-......-2-1

C=2+4+4+8+10-12-14+16+......-2006+2008+2010-2012

D=1-2-3-4+5-6-7-8+9-10-11-......-2010

Tính giá trị biểu thức

A=1-2+3+4-5-6+7+8-9-.....+2007+2008-2009-2010

B=\(1-\frac{1}{6}-\frac{1}{12}-\frac{1}{20}-\frac{1}{30}-...-\frac{1}{9900}\)

1/ Tìm x biết:\(\left(\frac{1}{x}-\frac{2}{3}\right)^{^{^2}}-\frac{1}{16}=0\) 

2/ Cho a ;b là 2 số chính phương lẻ liên tiếp. Chứng minh rằng :  (a-1).(b-1) chia hết cho 192

3/ Tính:

[-2008.57+1004.(-86)]:[32.74+16.(-48)]

1+2-3-4+5+6-7-8+9+10-...+2006-2007-2008+2009