Archived App (Last seen on 12 Jan 2026)
This is an archived listing of the app previously available on the App Store.
Exercise your logical thinking and mathematical skills with this number sequence puzzle game. Deduce missing numbers based on a specific formula across various game modes and difficulty levels. Offers detailed solutions and history tracking.
1.2
December 6, 2025
Improved display and performance, enhanced stability, and fixed minor issues.
Sum Within requires players to deduce missing numbers in a sequence based on the formula a[i] = a[i-1] + a[i-2] - i. You'll use the given numbers and the rule to fill in the blanks.
The provided description does not specify if Sum Within supports offline play. However, the Daily Challenge mode mentions competing with players worldwide, suggesting an online component for that feature.
Sum Within features four distinct game modes: Classic Mode for accuracy, Timed Mode for speed, Endless Mode for continuous play with limited mistakes, and Daily Challenge for a unique daily puzzle.
The game offers three difficulty levels: Easy (5 numbers, 1 blank, ±50 range), Medium (6-7 numbers, 2 blanks, ±100 range), and Hard (8 numbers, 3 blanks, ±200 range), allowing players to tailor the challenge.
Sum Within is rated '4+' by the app store, making it suitable for a wide range of young players and adults.
The latest version of Sum Within is 1.2, and it was last updated on December 6, 2025. This indicates relatively recent activity from the developer.
Yes, Sum Within includes complete game history tracking, allowing you to review your past performance and progress.
Sum Within provides detailed solution explanations for its puzzles, helping players understand the logic behind the correct answers.
