ơ kìa số to thé

\(10\cdot10=100\)

\(100\cdot100=10000\)

Tính:

10*10=100

100*100=10000

1000*1000=1000000

10000*10000=100000000

100000*100000=10000000000

1000000*1000000=1000000000000

10000000000*10000000000=100000000000000000000

=-(0,1+0,01+0,001+0,0001+0,00001)

=-0,11111

Đây là cách đơn giản nhất 

=-(0,1+0,01+0,001+0,0001+0,000001)

=-0,111101

Mk nhầm nha 

B = \(-\frac{1}{10}-\frac{1}{100}-\frac{1}{1000}-...-\frac{1}{1000000}\)

B = \(-\left(\frac{1}{10}+\frac{1}{10^2}+\frac{1}{10^3}+...+\frac{1}{10^6}\right)\)

Đặt A = \(\frac{1}{10}+\frac{1}{10^2}+\frac{1}{10^3}+...+\frac{1}{10^6}\)

10A = \(1+\frac{1}{10}+\frac{1}{10^2}+...+\frac{1}{10^5}\)

9A = 10A - A = \(1-\frac{1}{10^6}\)

=> A = \(\frac{1-\frac{1}{10^6}}{9}\)

=> B = \(-\left(\frac{1-\frac{1}{10^6}}{9}\right)\)

C=(0,1+0,01+0,001+...+0,000001)=-0,111111

mình ko chép đề bài

tao không biết

\(\frac{1}{10}+\frac{20}{100}+\frac{300}{1000}+\frac{40000}{100000}\)

\(=\frac{1}{10}+\frac{20}{10}+\frac{30}{10}+\frac{40}{10}\)

\(=\frac{1+2+3+4}{10}\)

\(=\frac{10}{10}\)

\(=1\)

1/10 + 20/100 + 300/1000 + 4000/10000

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

=10/10

=1

\(\frac{1}{10}+\frac{20}{100}+\frac{300}{1000}+\frac{4000}{10000}\)

\(=\frac{1}{10}+\frac{2}{10}+\frac{3}{10}+\frac{4}{10}\)

\(=\frac{1+2+3+4}{10}\)

\(=\frac{10}{10}\)

\(=1\)

tk mk nha

hello cac ban mong cac ban giai giup minh nhe

a  0,1  0,01  0,001  0,0001

b  0,84  0,225  0,6453  0,25789

TL:

a. 1/10 = 0,1

1/100 = 0,01

1/1000 = 0,001

1/10000 = 0,0001

b. 84/10 = 8,4

225/100 = 2,25

6453/1000 = 6,453

25789/10000 = 2,5789

HT~

-0,211111

Bài làm

       \(\frac{1}{10}+\frac{20}{100}+\frac{300}{1000}+\frac{4000}{10000}\)

\(=\frac{1}{10}+\frac{2}{10}+\frac{3}{10}+\frac{4}{10}\)

\(=\frac{1+2+3+4}{10}\)

\(=\frac{10}{10}\)

\(=1\)

# Học tốt #

\(\frac{1}{10}+\frac{20}{100}+\frac{300}{1000}+\frac{4000}{10000}\)

=\(\frac{1}{10}+\frac{2}{10}+\frac{3}{10}+\frac{4}{10}\)

= \(\frac{1+2+3+4}{10}\)

=\(\frac{10}{10}\)

= 1

Ta có : \(B=\frac{-1}{10}-\frac{1}{100}-\frac{1}{1000}-\frac{1}{10000}-\frac{1}{100000}\)

\(\Rightarrow B=-\left(\frac{1}{10}+\frac{1}{100}+\frac{1}{1000}+\frac{1}{10000}+\frac{1}{100000}\right)\)

Đặt \(A=\frac{1}{10}+\frac{1}{100}+\frac{1}{1000}+\frac{1}{10000}+\frac{1}{100000}\)

\(\Rightarrow10A=1+\frac{1}{10}+\frac{1}{100}+\frac{1}{1000}+\frac{1}{10000}\)

\(\Rightarrow10A-A=1-\frac{1}{100000}\)

\(\Rightarrow9A=\frac{99999}{100000}\)

\(\Rightarrow A=\frac{99999}{100000}.\frac{1}{9}=\frac{11111}{100000}\)

=> B = \(-\frac{11111}{100000}\)

\(A=\frac{-1}{10}-\frac{1}{100}-\frac{1}{1000}-\frac{1}{10000}-\frac{1}{100000}\)

\(\Rightarrow A=-\left(\frac{1}{10}+\frac{1}{100}+\frac{1}{1000}+\frac{1}{10000}+\frac{1}{100000}\right)\)

\(\Rightarrow A=-\left(\frac{10000}{100000}+\frac{1000}{100000}+\frac{100}{100000}+\frac{10}{100000}+\frac{1}{100000}\right)\)

\(\Rightarrow A=-\left(\frac{10000+1000+100+10+1}{100000}\right)\)

\(\Rightarrow A=-\left(\frac{11111}{100000}\right)\)

\(\Rightarrow A=\frac{-11111}{100000}\)