How to calculate sum of n integers and print the value of n

Question

C# using windows form

Answer 1

Take one variable sum and initialize it with 0 and take one more variable for number of Integer n you for loop and give condition upto total Number

for(i=0;i<number of Integer;i++)
{
sum+=i;
}

Answer 2

Please show us your attempt first.
What is the part you find difficult to do ?