Triangular number — AMC & AIME Problems
Practice every real AMC 8, AMC 10, AMC 12, and AIME problem that uses triangular number — a number theory concept — each with a professionally curated solution, many with a video solution too, from LIVE by Po-Shen Loh. Browse all concepts or the full past-contest archive.
All of these problems are used with official legal permission of the Mathematical Association of America (MAA).
AMC 10
2002 AMC 10B Problem 23 · 2004 AMC 10A Problem 24 · 2005 AMC 10A Problem 21 · 2005 AMC 10B Problem 22 · 2007 AMC 10B Problem 9 · 2013 AMC 10B Problem 13 · 2013 AMC 10B Problem 18 · 2014 AMC 10A Problem 24 · 2016 AMC 10A Problem 9 · 2016 AMC 10B Problem 4 · 2019 AMC 10A Problem 23 · 2021 AMC 10A Spring Problem 16 · 2024 AMC 10B Problem 4 · 2025 AMC 10A Problem 19
More number theory concepts
Chicken McNugget TheoremChinese Remainder Theoremcontinued fractiondigitsDiophantine EquationdivisibilityEuler’s Totient Functionfactorfactor countingFermat’s Little Theoremgreatest common divisorleast common multipleLegendre’s Formulamodular arithmeticmodular exponentiationmultiplemultiplicative orderpalindromeparityperfect powerperfect squarepower of 2primeprime factorizationsum of factorstrailing zerosunits digit