Théorie des Nombres

Sum of Positive Integers Calculator

Calculate the sum of consecutive positive integers quickly and easily. Enter the start and end numbers to find the sum using our intuitive online calculator.

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Understanding Sum of Positive Integers

The sum of positive integers, also known as the sum of natural numbers, is the result of adding a sequence of consecutive positive integers. For example, the sum of the first 5 positive integers (1, 2, 3, 4, 5) is 1 + 2 + 3 + 4 + 5 = 15.

Formula for Sum of Integers

For a range of positive integers from n1 to n2, the sum (S) can be calculated using the formula derived from the arithmetic series sum formula. A simplified approach leverages the formula for the sum of the first n natural numbers, which is given by:

$$ S_n = rac{n(n+1)}{2} $$

To find the sum from n1 to n2, we calculate the sum of the first n2 integers and subtract the sum of the first n1 - 1 integers. This is expressed as:

$$ S = rac{n_2(n_2+1)}{2} - rac{(n_1-1)n_1}{2} $$

Example

Let\'s calculate the sum of positive integers from 1 to 10:

  • n1 = 1
  • n2 = 10
  • Using the formula: S = (10 * (10 + 1)) / 2 - ((1 - 1) * 1) / 2 = (10 * 11) / 2 - 0 = 110 / 2 = 55

Therefore, the sum of positive integers from 1 to 10 is 55.