Đại số lớp 6
Các câu hỏi tương tự
Tìm số tự nhiên x
a) \(\dfrac{x}{2008}-\dfrac{1}{10}-\dfrac{1}{15}-\dfrac{1}{21}-....-\dfrac{1}{120}=\dfrac{5}{8}\)
b)\(\dfrac{1}{3.5}+\dfrac{1}{5.7}+\dfrac{1}{7.9}+....+\dfrac{1}{\left(2x+1\right).\left(2x+3\right)}=\dfrac{15}{93}\)
Bài 1 Tính
a) ( dfrac{-2}{3} + 1dfrac{1}{4} - dfrac{1}{6} ) : dfrac{-24}{10}
b) dfrac{13}{15} x 0.25 x 3 + ( dfrac{8}{15} - 1dfrac{19}{60} ) 1dfrac{23}{24}
c) ( dfrac{12}{32} + dfrac{5}{-20} - dfrac{10}{24} ) : dfrac{2}{3}
d) 4dfrac{1}{2} : ( 2.5 - 3dfrac{3}{4} ) + ( -dfrac{1}{2} )
e) dfrac{-5}{2} : ( dfrac{3}{4} - dfrac{1}{2} )
Đọc tiếp
Bài 1 Tính
a) ( \(\dfrac{-2}{3}\) + \(1\dfrac{1}{4}\) - \(\dfrac{1}{6}\) ) : \(\dfrac{-24}{10}\)
b) \(\dfrac{13}{15}\) x 0.25 x 3 + ( \(\dfrac{8}{15}\) - \(1\dfrac{19}{60}\) ) \(1\dfrac{23}{24}\)
c) ( \(\dfrac{12}{32}\) + \(\dfrac{5}{-20}\) - \(\dfrac{10}{24}\) ) : \(\dfrac{2}{3}\)
d) \(4\dfrac{1}{2}\) : ( 2.5 - \(3\dfrac{3}{4}\) ) + ( -\(\dfrac{1}{2}\) )
e) \(\dfrac{-5}{2}\) : ( \(\dfrac{3}{4}\) - \(\dfrac{1}{2}\) )
BT1: Tính nhanh
1) \(\left(\dfrac{-4}{9}+\dfrac{3}{7}\right):1\dfrac{1}{15}+\left(\dfrac{4}{7}-\dfrac{5}{9}\right):1\dfrac{1}{15}\)
2) \(3\dfrac{2}{9}.15\dfrac{4}{7}-3\dfrac{2}{9}.8\dfrac{1}{7}+3\dfrac{2}{9}.\dfrac{15}{7}-3\dfrac{2}{9}.\dfrac{1}{7}\)
thực hiện phép tính( hợp lí nếu có thể)
dfrac{-5}{9}+1dfrac{5}{9}.left(dfrac{3}{4}-dfrac{2}{5}right):7^2
1dfrac{13}{15}.0,75-left(dfrac{104}{195}+25%right).dfrac{24}{47}-3dfrac{12}{13}:3
1dfrac{13}{15}.left(0,5right)^2.3+left(dfrac{8}{15}-1dfrac{19}{60}right):1dfrac{23}{24}
tìm x
60%x+0,4x+x:32
-2x-dfrac{-3}{5}:left(0,5right)^2-1dfrac{1}{4}
left(dfrac{2}{3}-xright):dfrac{3}{4}dfrac{1}{5}
Đọc tiếp
thực hiện phép tính( hợp lí nếu có thể)
\(\dfrac{-5}{9}+1\dfrac{5}{9}.\left(\dfrac{3}{4}-\dfrac{2}{5}\right):7^2\)
\(1\dfrac{13}{15}.0,75-\left(\dfrac{104}{195}+25\%\right).\dfrac{24}{47}-3\dfrac{12}{13}:3\)
\(1\dfrac{13}{15}.\left(0,5\right)^2.3+\left(\dfrac{8}{15}-1\dfrac{19}{60}\right):1\dfrac{23}{24}\)
tìm x
\(60\%x+0,4x+x:3=2\)
\(-2x-\dfrac{-3}{5}:\left(0,5\right)^2=-1\dfrac{1}{4}\)
\(\left(\dfrac{2}{3}-x\right):\dfrac{3}{4}=\dfrac{1}{5}\)
Tính nhanh
a)(5dfrac{1}{7}- 3dfrac{3}{11}) - 2dfrac{1}{7}-1dfrac{8}{11}
b) (dfrac{1999}{2011}-dfrac{2011}{1999}) -(dfrac{-12}{1999}-dfrac{12}{2011})
c)(1-dfrac{1}{2})(1-dfrac{1}{3})............(1-dfrac{1}{2017})
d) dfrac{2}{15}.6dfrac{5}{11}+dfrac{5}{11}.dfrac{-2}{15}-dfrac{2}{15}.2015^0
e)dfrac{1}{6}-dfrac{1}{39}+dfrac{1}{51}:dfrac{1}{8}-dfrac{1}{12}+dfrac{1}{68}
Đọc tiếp
Tính nhanh
a)(5\(\dfrac{1}{7}\)- 3\(\dfrac{3}{11}\)) - 2\(\dfrac{1}{7}\)-1\(\dfrac{8}{11}\)
b) (\(\dfrac{1999}{2011}-\dfrac{2011}{1999}\)) -(\(\dfrac{-12}{1999}-\dfrac{12}{2011}\))
c)(1-\(\dfrac{1}{2}\))(1-\(\dfrac{1}{3}\))............(1-\(\dfrac{1}{2017}\))
d) \(\dfrac{2}{15}.6\dfrac{5}{11}+\dfrac{5}{11}.\dfrac{-2}{15}\)\(-\dfrac{2}{15}.2015^0\)
e)\(\dfrac{1}{6}-\dfrac{1}{39}+\dfrac{1}{51}\):\(\dfrac{1}{8}-\dfrac{1}{12}+\dfrac{1}{68}\)
tính:
dfrac{2}{5}xdfrac{1}{3}-dfrac{2}{15}:dfrac{1}{5}+dfrac{3}{5}xdfrac{1}{3}
2)left(3dfrac{1}{3}+2,5right):left(3dfrac{1}{6}-4dfrac{1}{5}right)-dfrac{11}{31}
3)left[6+left(dfrac{1}{2^{ }}right)^3-left|-dfrac{1}{2}right|right]:dfrac{3}{12}
4)dfrac{18}{37}+dfrac{8}{24}+dfrac{19}{37}-1dfrac{23}{24}+dfrac{2}{3}
5) left(-2right)^3xleft(dfrac{3}{4}-0,25right):left(2dfrac{1}{4}-1dfrac{1}{6}right)
6)left(dfrac{2}{5}right)^2+5dfrac{1}{2}xleft(45-2right)+dfrac{23}{-4}
7)dfrac{4}{9}-19dfrac{1}{3}-...
Đọc tiếp
tính:
\(\dfrac{2}{5}x\dfrac{1}{3}-\dfrac{2}{15}:\dfrac{1}{5}+\dfrac{3}{5}x\dfrac{1}{3}\)
2)\(\left(3\dfrac{1}{3}+2,5\right):\left(3\dfrac{1}{6}-4\dfrac{1}{5}\right)-\dfrac{11}{31}\)
3)\(\left[6+\left(\dfrac{1}{2^{ }}\right)^3-\left|-\dfrac{1}{2}\right|\right]:\dfrac{3}{12}\)
4)\(\dfrac{18}{37}+\dfrac{8}{24}+\dfrac{19}{37}-1\dfrac{23}{24}+\dfrac{2}{3}\)
5) \(\left(-2\right)^3x\left(\dfrac{3}{4}-0,25\right):\left(2\dfrac{1}{4}-1\dfrac{1}{6}\right)\)
6)\(\left(\dfrac{2}{5}\right)^2+5\dfrac{1}{2}x\left(45-2\right)+\dfrac{23}{-4}\)
7)\(\dfrac{4}{9}-19\dfrac{1}{3}-\dfrac{4}{9}x39\dfrac{1}{3}\)
8)\(\left(-\dfrac{1}{2}\right)^2:\dfrac{1}{4}-2x\left(-\dfrac{1}{2}\right)^2\)
9)\(125\%x\left(-\dfrac{1}{2}\right)^3:\left(1\dfrac{5}{16}-1,5\right)+2008^0\)
giúp mình nha mai mình học rùi 
Chứng tỏ rằng :dfrac{1}{101}+dfrac{1}{102}+...+dfrac{1}{299}+dfrac{1}{300}dfrac{2}{3}
Tính tích Adfrac{3}{4}.dfrac{8}{9}.dfrac{15}{16}...dfrac{899}{900}
Chứng tỏ rằng : dfrac{1}{5}+dfrac{1}{6}+dfrac{1}{7}+...+dfrac{1}{17} 2
Tính giá trị của biểu thức sau :
Mdfrac{1}{1.2.3}+dfrac{1}{2.3.4}+dfrac{1}{3.4.5}+...+dfrac{1}{10.11.12}
Đọc tiếp
Chứng tỏ rằng :\(\dfrac{1}{101}+\dfrac{1}{102}+...+\dfrac{1}{299}+\dfrac{1}{300}>\dfrac{2}{3}\)
Tính tích \(A=\dfrac{3}{4}.\dfrac{8}{9}.\dfrac{15}{16}...\dfrac{899}{900}\)
Chứng tỏ rằng : \(\dfrac{1}{5}+\dfrac{1}{6}+\dfrac{1}{7}+...+\dfrac{1}{17}< 2\)
Tính giá trị của biểu thức sau :
\(M=\dfrac{1}{1.2.3}+\dfrac{1}{2.3.4}+\dfrac{1}{3.4.5}+...+\dfrac{1}{10.11.12}\)
Tính \(A=\dfrac{1}{3}.\dfrac{1}{7}+\dfrac{1}{7}.\dfrac{1}{11}+\dfrac{1}{11}.\dfrac{1}{15}+...+\dfrac{1}{95}.\dfrac{1}{99}\)
BT1: Tính
1) \(3\dfrac{1}{2}+15\dfrac{4}{9}:\dfrac{26}{7}-2\dfrac{4}{9}:\dfrac{26}{7}\)
2) \(34.\left(2\dfrac{1}{17}-3\dfrac{5}{24}\right)+\dfrac{1}{2}\)