2025AIME2 P4--84°–60°–36° Triangle + Midpoint Triangle: Arc-Length Combo

 2025AIME2 P3--Log Telescoping Product: Simplify the Chain of Bases

 2025AIME2 P2--Divisibility Puzzle: Sum of n with (n+2) | 3(n+3)(n²+9)

 2025AIME2 P1-Six Collinear, One Off-Line: Area of △BGE (Geometry/Coordinates)

 2019AMC12A P25 SOL2--Angle Iteration Map & Invariant Linearization

 2019AMC12A P25 SOL1--Iterative Geometry

 2019AMC12A P24--Factorials/Valuation

 2019AMC12A P23 SOL2--Log Transform & Closed-Form Recurrence

 2019AMC12A P23 SOL1--Strange Operation/Logs

 2019AMC12A P22--Invariant/Monovariant

 2019AMC12A P21 SOL2--Root Pairing & Modulus-Conjugate

 2019AMC12A P21 SOL1--Complex/Roots of Unity

 2019AMC12A P20--Triangle Lengths

 2019AMC12A P19--Lattice Paths

 2019AMC12A P18--Complex Fractions

 2019AMC12A P17--Vectors/Analytic Geo

 2019AMC12A P16--Number Theory Build

 2019AMC12A P15--Quadratic Vertex

 2019AMC12A P14--Combinatorics

 2019AMC12A P13--System Tricks

 2019AMC12A P12--Circles/Power

 2019 AMC12A P11--Inequalities

 2019 AMC12A P10--Probability/Counting

 2019 AMC12A P9--Function & Equation

 2019 AMC12A P7--Divisibility/Residue