The first term of an arithmetic sequence is $\mathrm{n}$ and the ${\mathrm{n}}^{\text{th}}$ term is $1$ . Sum of how many terms, starting from the first term, of this sequence is zero? If the answer is $2n+k$, find $k$.

Consider the numbers between $100$ and $300$ which leaves remainder $2$ on division by $3$.

Which is the first number in this sequence?

Consider the numbers between $100$ and $300$ which leaves remainder $2$ on division by $3$.

Which is the last number in this sequence?

Consider the numbers between $100$ and $300$ which leaves remainder $2$ on division by $3$.

How many such numbers are there in this sequence?

Consider the numbers between $100$ and $300$ which leaves remainder $2$ on division by $3$.

Find the sum of all the numbers of the sequence?