Question

\(A=\dfrac{1}{2.3}+\dfrac{1}{3.4}+...+\dfrac{1}{99.100}\)

Answer 1

\(A=\dfrac{1}{2.3}+\dfrac{1}{3.4}+...+\dfrac{1}{99.100}\)

\(=\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{3}-\dfrac{1}{4}+...+\dfrac{1}{99}-\dfrac{1}{100}=\dfrac{1}{2}-\dfrac{1}{100}=\dfrac{49}{100}\)

Answer 2

`A=1/(2.3) + 1/(3.4) +........ +1/(99.100)`

`=1/2-1/3+1/3-1/4+......+1/99-1/100`

`=1/2-1/100`

`=49/100`

Answer 3

nhanh lên 

Answer 4

\(A=\dfrac{1}{2.3}+\dfrac{1}{3.4}+...+\dfrac{1}{99.100}\)

    \(=\dfrac{1}{1}-\dfrac{1}{2}+\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{3}-\dfrac{1}{4}+...+\dfrac{1}{99}-\dfrac{1}{100}\)

    \(=\dfrac{1}{1}-\dfrac{1}{100}\)

    \(=\dfrac{100-1}{100}\)

    \(=\dfrac{99}{100}\)