Question

tinh gia tri cua bieu thuc \(\frac{1}{1\times2}+\frac{1}{2\times3}+........+\frac{1}{99\times100}\)

Answer 1

\(\frac{1}{1x2}+\frac{1}{2x3}+...+\frac{1}{99x100}=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+...+\frac{1}{99}-\frac{1}{100}=1-\frac{1}{100}=\frac{99}{100}\)

Answer 2

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

Answer 3

99/100 đúng đó nhơ minh nhé hi hi

Answer 4

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

1/1-1/100

99/100

k nha

Answer 5

Ta có 

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

= 1/1 - 1/100 (vì các số kề nhau giảm ước cho nhau)

=99/100.

Answer 6

\(\frac{99}{100}\) nha đúng 100% 

Answer 7

99/100 nhé cho mk

Answer 8

\(\frac{1}{1.2}+\frac{1}{2.3}+...+\frac{1}{99.100}\)

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

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

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