Figurate Numbers Fort

Levels 20–99 · figurateNumbers

A fort built from triangular stones and square tiles. Master triangular, square, and pentagonal numbers to unlock its chambers.

Study Before You Play

Brush up on these topics to sharpen your skills for this zone.

Special Numbers & Sequences

Triangular, square, and pentagonal numbers are the classic figurate number families.

Sequences & Patterns

Figurate numbers form sequences with elegant closed-form formulas.

Counting Principle

C(n+1, 2) = T(n), connecting triangular numbers to combinations.