=1/10+2/10+3/10+4/10+5/10+6/10

=21/10

ô hô hô

sao mà bị mắng?

hihihihahahaha

P = 1/3 + -3/4 + 3/5 + -1/36 + 1/15 + -2/9

   =60/180 - 135/180 + 108/180 - 5/180 + 12/180 - 40/180

   =60-135+108-5+12-40/180

   =0/180=0

Nhớ k cho mik nha, Hok tốt !

120 : 30= ?

\(a) {4\over12}={4.5\over12.5}={20\over60}\)

    \({1\over5}={1.12\over5.12}={12\over60}\)

    \({-4\over15}={-4.4\over15.5}={-16\over60}\)

b)\({-7\over10}={-7.3\over10.3}={-21\over20}\)

    \({1\over2}={1.15\over2.15}={15\over30}\)

    \({-4\over15}={-4.2\over15.2}={-8\over30}\)

c)\({-5\over14}={-5.30\over14.30}={-150\over420}\)

    \({3\over20}={3.21\over20.21}={63\over420}\)

    \({-4\over21}={-4.20\over21.20}={-80\over420}\)

d)\({4\over18}={4.5\over18.5}={20\over90}\)

    \({1\over18}={1.18\over5.18}={18\over90}\)

    \({-6\over15}={-6.6\over15.6}={-36\over90}\)

Nói lời giữ lời nha ^_^..........Mệt wá........

a)4/12=1.5/12.5=5/60

  1/5=1.12/5.12=5/60

  -4/15=-4.4/15.4=-16/60

b)-7/10=-7.3/10.3=-21/30

   1/2=1.15/2.15=15/30

   -4/15=-4.2/15.2=-8/30

c)-5/14=-5.30/14/30=150/420

   3/20=3.21/20.21=63/420

   -4/21=-4.20/21.20=-80/420

d)4/18=4.5/18.5=20/90

   1/5=1.18/5.18=18/90

   -6/15=-6.6/15.6=-36/90

a đu, thế mà bảo là lớp 6 hả

i don'n know

#)Giải :

Bài 1 :

\(A=\frac{1}{5}+\frac{1}{10}+\frac{1}{20}+...+\frac{1}{1280}\)

\(\Rightarrow A\times2=\frac{2}{5}-\left(\frac{1}{5}+\frac{1}{10}+\frac{1}{20}+...+\frac{1}{1280}\right)-\frac{1}{1280}\)

\(\Rightarrow A\times2=\frac{2}{5}-A-\frac{1}{1280}\)

\(\Rightarrow A\times2+A=\frac{2}{5}-\frac{1}{1280}\)

\(\Rightarrow A=\frac{2}{5}-\frac{1}{1280}\)

\(\Rightarrow A=\frac{511}{1280}\)

#)Giải :

Bài 2 :

\(B=\frac{1}{3}+\frac{1}{9}+\frac{1}{27}+...+\frac{1}{59049}\)

\(B=\frac{1}{3}+\frac{1}{3^2}+\frac{1}{3^3}+...+\frac{1}{3^{10}}\)

\(3B=1+\frac{1}{3}+\frac{1}{3^2}+...+\frac{1}{3^9}\)

\(3B-B=\left(1+\frac{1}{3}+\frac{1}{3^2}...+\frac{1}{3^9}\right)-\left(\frac{1}{3}+\frac{1}{3^2}+\frac{1}{3^3}+...+\frac{1}{3^{10}}\right)\)

\(2B=1-\frac{1}{3^{10}}\)

\(B=\frac{1-\frac{1}{3^{10}}}{2}\)

Bạn ơi bài 2 m ko hỉu

a) 10 lần

b) 10 lần

c) 10 lần

gấp10

b,10

c,10

tất cả đều gấp 10 nha

a b c đều là10