This math topic focuses on calculating the sum of all integers from 1 to a given number \( N \), with each question presenting a different series end, such as 15, 14, 11, 12, and 9. The task involves recognizing and applying the formula for the sum of an arithmetic series or deducing the sum through pattern recognition. Each question presents multiple-choice answers, challenging the learner to select the correct sum for the integers specified.

Work on practice problems directly here, or download the printable pdf worksheet to practice offline.