The sum of the first $n$ natural numbers can be computed using the following formula:

$S = \frac{n(n+1)}{2}$

This formula allows you to calculate the sum of the sequence $1 + 2 + \cdots + n$.

Example:

For $n = 5$: $S = \frac{5(5+1)}{2} = \frac{5 \times 6}{2} = 15$

Would you like more details on how this formula is derived or have any further questions?

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Here are five related questions to expand your understanding:

1. How can you prove the sum formula for $n$ natural numbers using induction?
2. What is the sum of the first $n$ even numbers?
3. How would you modify the formula to sum only the odd numbers up to $n$?
4. How does the sum formula change for an arithmetic sequence with a common difference other than 1?
5. Can you find the sum of squares of the first $n$ natural numbers?

Tip: Understanding the sum of sequences helps solve many types of arithmetic and algebraic problems effectively!