Summation is an engaging and fast-paced number puzzle game where players must think quickly and strategically to clear the grid before it fills up. The game operates on a Tetris-style mechanic, where a full line of numbers continuously drops down every few seconds. The player's objective is to identify and select two numbers that sum up to the target number displayed on the panel. Upon selecting a correct pair, those numbers disappear, creating space in the grid. If two identical numbers are selected, the entire row is destroyed, giving the player a powerful way to clear space efficiently.
The challenge intensifies as more lines drop in at an increasing pace, requiring fast mental calculations and quick reflexes. The game ends when the grid is completely filled with numbers and no valid moves remain.