Question

Tính nhanh BT sau:

\(\dfrac{1}{500}+\dfrac{3}{500}+\dfrac{5}{500}+......+\dfrac{95}{500}+\dfrac{97}{500}+\dfrac{99}{500}\)

Answer 1

\(\dfrac{1}{500}+\dfrac{3}{500}+\dfrac{5}{500}+...+\dfrac{95}{500}+\dfrac{97}{500}+\dfrac{99}{500}\)

\(=\left(\dfrac{1}{500}+\dfrac{99}{500}\right)+\left(\dfrac{3}{500}+\dfrac{97}{500}\right)+\left(\dfrac{5}{500}+\dfrac{95}{500}\right)+...\)

\(=\dfrac{1}{5}+\dfrac{1}{5}+\dfrac{1}{5}+...\) ( 50 số )

\(=\dfrac{1}{5}.50\)

\(=10\)

Answer 2

Nguyễn Huy TúAce Legonasoyeon_Tiểubàng giảiTrần Việt Linh

Võ Đông Anh TuấnHoàng Lê Bảo NgọcPhương An

Answer 3

Đặt:

\(A=\dfrac{1}{500}+\dfrac{3}{500}+\dfrac{5}{500}+...+\dfrac{97}{500}+\dfrac{99}{500}\)

\(\Rightarrow A=\dfrac{1+3+5+...+97+99}{500}\)

\(\Rightarrow A=\dfrac{\dfrac{\left[\left(99-1\right):2+1\right].\left(99+1\right)}{2}}{500}=\dfrac{2500}{500}\)

\(\Rightarrow A=5\)

Chúc bạn học tốt!

Answer 4

=(1/500)( 1+3+5+....+99)

=(1/500).99.100/2

=99/10