Tính
M=1/3+1/6+1/10+1/15+...+2/2004*2005
Mọi người giúp mình với ạ...
Tks!!
Bài 1: Tính nhanh
a) -5/7-(-5/67) + 13/30 + 1/2 + (-11/6) + 17/14 - (-2/5) b) 3/5 : (-1/15 - 1-6) +3/5 : (1/3 + 16/15 c) (3 - 1/4 + 2/3)-(5 - 1/3 - 6/5) - (6 - 7/4 + 3/2) d) 1/3 + 1/3^2 + 1/3^3 +......+ 1/3^2004 + 1/3^2005 Mọi người giúp em với em cảm ơn ạ =))))))))
a)(-0,25).4/17.(-3 5/21).(-7/12)
b) (-2/5).4/15+(-3/10).4/15
c)21-3 3/4:(3/8-1/6)
d) (-3/4+2/5):3/7+(3/5+-1/4):3/7
GIÚP MÌNH VỚI Ạ. MÌNH CẦN GẤP VÀO SÁNG NAY. CẢM ƯN NỌI NGƯỜI NHÌU!
CÔ NGUYỄN THỊ THƯƠNG HOÀI GIÚP EM VỚI Ạ
a) \(...=-\dfrac{1}{4}.\dfrac{4}{17}.\left(-\dfrac{63}{21}\right).\left(-\dfrac{7}{12}\right)\)
\(=-\dfrac{1}{17}.\dfrac{63}{21}.\dfrac{7}{12}\)
\(=-\dfrac{7}{68}\)
b) \(...=-\dfrac{2}{5}.\dfrac{4}{15}-\dfrac{3}{10}.\dfrac{4}{15}\)
\(=\dfrac{4}{15}\left(-\dfrac{2}{5}-\dfrac{3}{10}\right)\)
\(=\dfrac{4}{15}\left(-\dfrac{4}{10}-\dfrac{3}{10}\right)\)
\(=\dfrac{4}{15}.\left(-\dfrac{7}{10}\right)=-\dfrac{14}{75}\)
c) \(...=21-\dfrac{15}{4}:\left(\dfrac{9}{24}-\dfrac{4}{24}\right)\)
\(=21-\dfrac{15}{4}:\dfrac{5}{24}\)
\(=21-\dfrac{15}{4}.\dfrac{24}{5}\)
\(=21-3.6=3\)
d) \(...=\left(-\dfrac{3}{4}+\dfrac{2}{5}\right).\dfrac{7}{3}+\left(\dfrac{3}{5}-\dfrac{1}{4}\right).\dfrac{7}{3}\)
\(=\dfrac{7}{3}\left(-\dfrac{3}{4}+\dfrac{2}{5}+\dfrac{3}{5}-\dfrac{1}{4}\right)\)
\(=\dfrac{7}{3}\left(-\dfrac{3}{4}-\dfrac{1}{4}+\dfrac{2}{5}+\dfrac{3}{5}\right)\)
\(=\dfrac{7}{3}\left(-1+1\right)=0\)
\(\frac{1}{3}+\frac{1}{6}+\frac{1}{10}+\frac{1}{15}+............+\frac{2}{2004\times2005}\)
giúp mình nhé
a)(-0,25).4/17.(-3 5/21).(-7/12)
b) (-2/5).4/15+(-3/10).4/15
c)21-3 3/4:(3/8-1/6)
d) (-3/4+2/5):3/7+(3/5+-1/4):3/7
GIÚP MÌNH VỚI Ạ. MÌNH CẦN GẤP VÀO SÁNG NAY. CẢM ƯN NỌI NGƯỜI NHÌU!
a)(-0,25).4/17.(-3 5/21).(-7/12)
= -1/17 . (-68/21) . ( -7/21)
= -4/63
b) (-2/5).4/15+(-3/10).4/15
= 4/15. [-2/5 + (-3/10)]
= 4/15 . (-7/10)
= -14/75
c)21-3 3/4:(3/8-1/6)
= 21 - 15/4 : 5/24
= 21 - 18
= 3
d) (-3/4+2/5):3/7+(3/5+-1/4):3/7
= [(-3/4 + 2/5) + (3/5 + -1/4)] : 3/7
= [-7/20 + (-17/20)] : 3/7
= -6/5 : 3/7
= -14/5
tính và nêu cách tính giúp mình với ạ
1/2004 +2 +1/2004 +3 +2/2004
\(\frac{1}{2004}+2+\frac{1}{2004}+3+\frac{2}{2004}\)
\(=\frac{1}{2004}+\frac{2}{1}+\frac{1}{2004}+\frac{3}{1}+\frac{2}{2004}\)
\(=\frac{1}{2004}+\frac{4008}{2004}+\frac{1}{2004}+\frac{6012}{2004}+\frac{2}{2004}\)
\(=\frac{4009}{2004}+\frac{1}{2004}+\frac{6012}{2004}\)\(+\frac{2}{2004}\)
\(=\frac{4010}{2004}+\frac{6012}{2004}+\frac{2}{2004}\)
\(=\frac{10022}{2004}+\frac{2}{2004}\)
\(=\frac{10024}{2004}\)
C=1=2-3-4+5+6-7-8+9+...+2002-2003-2004
D=1+3+32+33+....+320
MỌI NGƯỜI GIÚP MÌNH VỚI Ạ
a)-15/4:21/-10
b)-7/14:(-0,14)
c)(-11/15): 1 1/10
d)2 1/7 :1 1/14
GIÚP MÌNH VỚI Ạ. MÌNH CẦN GẤP. CẢM ƠN MỌI NGƯỜI NHIỀU!
a) \(\dfrac{-15}{4}:\dfrac{21}{-10}=\dfrac{-15}{4}.\dfrac{-10}{21}=\dfrac{25}{14}\)
b) \(\dfrac{-7}{14}:\left(-0,14\right)=\dfrac{-7}{14}.\dfrac{-50}{7}=\dfrac{25}{7}\)
c) \(\left(\dfrac{-11}{15}\right):1\dfrac{1}{10}=\dfrac{-11}{15}.\dfrac{10}{11}=\dfrac{-2}{3}\)
d) \(2\dfrac{1}{7}:1\dfrac{1}{14}=\dfrac{15}{7}.\dfrac{14}{15}=2\)
\(a.-\dfrac{15}{4}:\left(\dfrac{21}{-10}\right)\)
\(=-\dfrac{15}{4}\cdot\left(-\dfrac{10}{21}\right)\)
\(=\dfrac{25}{14}\)
\(b.-\dfrac{7}{14}:\left(-0,14\right)\)
\(=-\dfrac{1}{2}:\left(-\dfrac{7}{50}\right)\)
\(=\dfrac{25}{7}\)
\(c.\left(-\dfrac{11}{15}\right):\left(1\dfrac{1}{10}\right)\)
\(=\left(-\dfrac{11}{15}\right):\dfrac{11}{10}\)
\(=-\dfrac{2}{3}\)
\(d.\left(2\dfrac{1}{7}\right):\left(1\dfrac{1}{14}\right)\)
\(=\dfrac{15}{7}:\dfrac{15}{14}\)
\(=2\)
a) \(\dfrac{-15}{4}:\dfrac{21}{-10}=\dfrac{-15}{4}.\dfrac{-10}{21}=\dfrac{25}{14}\)
b) \(\dfrac{-7}{14}:\left(-0,14\right)=\dfrac{-7}{14}:\dfrac{-7}{50}=\dfrac{-7}{14}.\dfrac{50}{-7}=\dfrac{25}{7}\)
c) \(\dfrac{-11}{15}:1.\dfrac{1}{10}=\dfrac{-11}{15}.\dfrac{1}{10}=\dfrac{-11}{150}\)
d) \(\dfrac{21}{7}:1.\dfrac{1}{14}=3.\dfrac{1}{14}=\dfrac{3}{14}\)
tính giá trị biểu thức
[a] 1/3-2/15+14/15
[b] 3/5 +4-6/7
[c] 1/7+2/9+3/10+7/9+6/7+7/10
[d]3/4+5/8-5/6
mình cần gấp,các bạn trả lời nhanh giúp mình với ạ
\(\dfrac{1}{3}\)-\(\dfrac{2}{15}\)+\(\dfrac{14}{15}\)=\(\dfrac{3}{15}\)-\(\dfrac{2}{15}\)+\(\dfrac{14}{15}\)
=\(\dfrac{13}{15}\)
\(\dfrac{3}{5}\)+4-\(\dfrac{6}{7}\)=\(\dfrac{3}{5}\)+\(\dfrac{20}{5}\)-\(\dfrac{6}{7}\)=\(\dfrac{23}{5}\)-\(\dfrac{6}{7}\)=\(\dfrac{161}{35}\)-\(\dfrac{30}{35}\)=\(\dfrac{131}{35}\)
a)3/8+15/-25+3/5
b)-5/18+23/45-9/10
c)-5/12+ 1 5/18-2,25
d)5/6+2/3-0,5
GIÚP MÌNH VỚI Ạ. MÌNH CẦN GẤP. CẢM ƠN MỌI NGƯỜI!
a) \(\dfrac{3}{8}+\dfrac{15}{-25}+\dfrac{3}{5}\)
\(=\dfrac{-9}{40}+\dfrac{3}{5}\)
\(=\dfrac{3}{8}\)
b) \(\dfrac{-5}{18}+\dfrac{23}{45}-\dfrac{9}{10}\)
\(=\dfrac{7}{30}-\dfrac{9}{10}\)
\(=\dfrac{-2}{3}\)
c) \(\dfrac{-5}{12}+\dfrac{15}{18}-2,25\)
\(=\dfrac{5}{12}-2,25\)
\(=\dfrac{-11}{6}\)
d) \(\dfrac{5}{6}+\dfrac{2}{3}-0,5\)
\(=\dfrac{3}{2}-0,5\)
\(=1\)