\(2\frac{3}{13}\cdot\frac{26}{58}\cdot4\cdot2\frac{15}{24}\cdot\frac{8}{21}=\frac{29}{13}\cdot\frac{26}{58}\cdot4\cdot\frac{21}{8}\cdot\frac{8}{21}=\frac{29\cdot26\cdot4\cdot21\cdot8}{13\cdot58\cdot8\cdot21}=\frac{1\cdot2\cdot4\cdot1\cdot1}{1\cdot2\cdot1\cdot1}=\frac{1\cdot4}{1}=4\)
Tính nhanh :
A = \(\frac{1,25\times10\div0,25\times24,4\times2}{6,1\times2\times6,25\times4\div0,5}+\left(1-\frac{1}{2}\right)\times\left(1-\frac{1}{3}\right)\times\left(1-\frac{1}{4}\right).........\left(1-\frac{1}{19}\right)\times\left(1-\frac{1}{20}\right)\)
Tìm x, biết: \(x\times\left(44+\frac{2010}{1\times2}+\frac{2006}{2\times3}+\frac{2000}{3\times4}+...+\frac{32}{44\times45}\right)=\frac{44}{45}\)
tính giá trị biểu thức: \(\frac{1\times2\times3}{1\times6\times8}\times\frac{6\times4\times5}{3\times2\times2\times10}\)
Tìm \(x\):
\(\left(\frac{1}{1\times2}+\frac{1}{2\times3}+\frac{1}{3\times4}+.....\frac{1}{2009\times2010}\right)\times x=2009\)
Tích \(\frac{1\times2\times3\times4\times...\times190}{2\times3\times4\times...\times191}\) sau đây có tận cùng bằng chữ số nào ?
tính giá trị biểu thúc : \(\frac{1}{2}\times\frac{2\times6}{3\times6\times8}\times\frac{4\times6}{6\times2\times2}\times\frac{4\times5\times2}{2\times8\times10}\)
Tính nhanh:\(\frac{1+2}{1\times2}+\frac{1+2+3}{1\times2\times3}+...+\frac{1+2+...+999}{1\times2\times...\times999}+\frac{1+2+...+999+1000}{1\times2\times...\times999\times1000}\)
Tính nhanh:\(\frac{1\times2}{1+2}+\frac{1\times2\times3}{1+2+3}+..+\frac{1\times2\times...\times999}{1+2+...+999}+\frac{1\times2\times...\times999\times1000}{1+2+...+999+1000}\)
1.Tính nhanh
a,\(\frac{1}{1\times4}+\frac{1}{4\times7}+............+\frac{1}{97\times100}\)
b,\(\frac{1}{2}\times\frac{2}{3}\times\frac{3}{4}\times...........\times\frac{99}{100}\)
c,\(\frac{3}{4}\times\frac{8}{9}\times\frac{15}{16}\times...........\times\frac{99}{100}\)
d,\(\left(\frac{1}{2}+1\right)\times\left(\frac{1}{3}+1\right)\times\left(\frac{1}{4}+1\right)\times............\times\left(\frac{1}{99}+1\right)\)
e,\(\left(1-\frac{1}{2}\right)\times\left(1-\frac{1}{3}\right)\times\left(1-\frac{1}{4}\right)\times..........\times\left(1-\frac{1}{100}\right)\)