`1:(1 1/2 xx 1 1/3 xx 1 1/4 xx ... xx 1 1/99 )`
`= 1 : (3/2 xx 4/3 xx 5/4 xx ... xx 100/99)`
`= 1 : 100/2`
`= 1 xx 2/100`
`= 2/100`
`=1/50`
Bài 5: (Đề 2) Tính
a) \(2-1\dfrac{5}{6}+2\dfrac{2}{3}\)=........
b) \(\dfrac{5}{9}x\left(2\dfrac{5}{6}-1\dfrac{2}{3}\right)\)=..........
c)\(1\dfrac{1}{3}:\left(2+1\dfrac{1}{6}:2\dfrac{5}{6}\right)\)=..........
d) \(2\dfrac{3}{5}:\dfrac{3}{4}x1\dfrac{4}{5}\) =..........
Bài 7: (Đề 2) Tính nhanh
\(1\dfrac{1}{2}x1\dfrac{1}{3}x1\dfrac{1}{4}x...x1\dfrac{1}{999}\)
Tinh bang cach thuan tien:
a) \(1\dfrac{1}{2}x1\dfrac{1}{3}x1\dfrac{1}{4}\)
b) \(1\dfrac{1}{2}:1\dfrac{1}{3}:1\dfrac{1}{4}\)
1\(\dfrac{1}{3}\)x1\(\dfrac{1}{8}\)x1\(\dfrac{1}{15}\)x1\(\dfrac{1}{24}\)x1\(\dfrac{1}{35}\)
Tính
1\(\dfrac{1}{12}x1\dfrac{1}{13}x1\dfrac{1}{14}\) x ... x \(1\dfrac{1}{2005}\)
Giá trị của biểu thức: 2\(\dfrac{3}{5}\)x\(\dfrac{1}{4}\)x1\(\dfrac{1}{2}\)
mọi người giúp mình câu: \(\dfrac{8}{10}+\dfrac{3}{5}x1\dfrac{1}{9}:\dfrac{4}{55}\)
\(\dfrac{\left(\dfrac{1}{6}+\dfrac{1}{10}+\dfrac{1}{15}\right):\left(\dfrac{1}{6}+\dfrac{1}{10}-\dfrac{1}{15}\right)}{\left(\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{4}-\dfrac{1}{5}\right):\left(\dfrac{1}{4}-\dfrac{1}{6}\right)}=\)
\(A=\dfrac{1}{15}+\dfrac{1}{35}+\dfrac{1}{65}+...+\dfrac{1}{99}=\dfrac{16}{x}\)
\(B=\dfrac{5}{6}+\dfrac{11}{12}+\dfrac{19}{20}+\dfrac{29}{30}+\dfrac{41}{42}+\dfrac{55}{56}+\dfrac{x}{16}\)\(C=\left(1-\dfrac{1}{4}\right)\times\left(1-\dfrac{1}{9}\right)\times\left(1-\dfrac{1}{16}\right)\times...\times\left(1-\dfrac{1}{100}\right)=\dfrac{22}{x}\)
m.ng giúp em với
