a,\(\frac{1}{7\cdot8}\)=\(\frac{1}{56}\)
\(\frac{1}{7}-\frac{1}{8}\)=\(\frac{1}{56}\)
Nên ta điền dấu (=) vào ô trống
b, tương tự như phần a,
Chúc bạn học giỏi nhé !
1,Tính nhanh
a,3x\(\left(\frac{1}{7}+\frac{1}{3}-\frac{3}{14}\right):\frac{11}{14}\)
b,\(\left(\frac{21}{8}+\frac{1}{2}\right):\frac{5}{6}\)
3,Tìm x,biết
a,\(\frac{1}{3}+\frac{1}{6}+\frac{1}{10}+......+\frac{2}{x\cdot\left(x+1\right)}=\frac{2016}{2018}\)
b,720:\(720:[41-\left(2\cdot x-5\right)]=120\)
a)\(\frac{11}{9}+\frac{7}{6}\cdot\left(2-\frac{1}{3}\right)\)
b)\(1\frac{1}{21}:\left(15,75-15\frac{1}{4}\right)+2\frac{1}{12}:\left(7\frac{3}{4}-7,25\right)\)
Điền dấu (>, <, =) thích hợp vào ô trống:
\(3\frac{1}{5} - \frac{8}{3} \square \frac{{17}}{5} - 2\frac{{12}}{{15}}\)
\(a,\left(1-\frac{1}{2}\right)\cdot\left(1-\frac{1}{3}\right)\cdot\left(1-\frac{1}{4}\right)\cdot......\left(1-\frac{1}{18}\right)\cdot\left(1-\frac{1}{19}\right)\cdot\left(1-\frac{1}{20}\right)\)
Điền dấu thích hợp vào chỗ chấm :
\(\frac{1}{7}+\frac{1}{13}+\frac{1}{25}+\frac{1}{49}+\frac{1}{97}.....\frac{1}{3}\)
\(\left(1-\frac{1}{4}\right)\left(1-\frac{1}{9}\right)\left(1-\frac{1}{16}\right)\cdot....\cdot\left(1-\frac{1}{256}\right)\cdot x=\frac{108}{7}\)
\(a,\frac{18}{17}-\left(\frac{7}{4}-\frac{1}{5}\right):\frac{1}{2}\)
\(b,\frac{8}{5}-\frac{1}{2}:\frac{1}{4}x\left(\frac{3}{7}+\frac{1}{4}\right)\)
\(A=\frac{1}{2\cdot2}+\frac{1}{3\cdot3}+\frac{1}{4\cdot4}+\frac{1}{5\cdot5}+\frac{1}{6\cdot6}+\frac{1}{7\cdot7}+\frac{1}{8\cdot8}+\frac{1}{9\cdot9}\)
HÃY CHỨNG MINH :
\(\frac{2}{5}< A< \frac{8}{9}\)
\(A=\frac{1}{2\cdot2}+\frac{1}{3\cdot3}+\frac{1}{4\cdot4}+\frac{1}{5\cdot5}+\frac{1}{6\cdot6}+\frac{1}{7\cdot7}+\frac{1}{8\cdot8}+\frac{1}{9\cdot9}\)
HÃY CHỨNG MINH \(\frac{2}{5}< S< \frac{7}{8}\)
