Question

1+3+5+7+...+999

Answer 1

\(\LARGE\color{purple}{ \bf d=2 }\)
\(\LARGE\color{purple}{ \bf a_n=a_1+d(n-1) }\) , in your case, \(\LARGE\color{purple}{ \bf a_n=1+2(n-1) }\) for any n.


What exactly do you need to find ?

Answer 2

Sum of all terms?

Answer 3

To find the sum using Gauss's approach

Answer 4

1+999=1000
3+997=1000
5+995=1000
.
.
Just find out how many such pairs are there