Question

Find the sum of the positive even integers up and including $50$.

Answer 1

Finding the sum of the positive even integers up and including $50$:

There are $25$ even numbers between $1$to $50$
Sum of first $\mathrm{n}$ even numbers$=\mathrm{n}(\mathrm{n}+1)$
$$\begin{gathered} =25(25+1) \\ =25\left(26\right) \\ =650 \end{gathered}$$

Hence, the answer is $650$.