Question

\(\frac{1}{1x2}+\frac{1}{2x3}+.....+\frac{1}{99x100}\)

Answer 1

là 99/100

Answer 2

Ta có :\(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+......+\frac{1}{99.100}\) 

\(=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+......+\frac{1}{99}-\frac{1}{100}\)

\(=1-\frac{1}{100}\)

\(=\frac{99}{100}\)

Answer 3

\(\frac{1}{1\times2}+...+\frac{1}{99\times100}\)

= \(\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-...+\frac{1}{99}-\frac{1}{100}\)

= \(\frac{1}{1}-\frac{1}{100}=\frac{99}{100}\)

Answer 4

Ta có :

   \(1-\frac{1}{1}+\frac{1}{2}-\frac{1}{2}-\frac{1}{3}+...+\frac{1}{99}-\frac{1}{100}\)

\(=1-\frac{1}{100}\)

\(=\frac{100}{100}-\frac{1}{100}\)

\(=\frac{99}{100}\)

Answer 5

\(=\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+...+\frac{1}{9}-\frac{1}{10}\)

\(=\frac{1}{1}-\frac{1}{10}=\frac{10}{10}-\frac{1}{10}=\frac{9}{10}\)

Answer 6

\(\frac{1}{1x2}+\frac{1}{2x3}+....+\frac{1}{99x100}\)

\(=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+...+\frac{1}{99}-\frac{1}{100}\)

\(=1-\frac{1}{100}\)

\(=\frac{99}{100}\)

Answer 7

\(\frac{1}{1x2}+\frac{1}{2x3}+....+\frac{1}{99x100}\)

\(=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+...+\frac{1}{99}-\frac{1}{100}\)

\(=1-\frac{1}{100}\)

\(=\frac{99}{100}\)

Answer 8

\(\frac{1}{1x2}+\frac{1}{2x3}+....+\frac{1}{99x100}\)

\(=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+...+\frac{1}{99}-\frac{1}{100}\)

\(=1-\frac{1}{100}\)

\(=\frac{99}{100}\)

Answer 9

\(\frac{1}{1x2}+\frac{1}{2x3}+....+\frac{1}{99x100}\)

\(=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+...+\frac{1}{99}-\frac{1}{100}\)

\(=1-\frac{1}{100}\)

\(=\frac{99}{100}\)

Answer 10

99/100

Answer 11

99/100 nha bạn!tk mình nha

Answer 12

= 1/1-1/2+1/2-1/3+1/3-...+1/99-1/100

=1/1-1/100=99/100