Number base — AMC & AIME Problems
Practice every real AMC 8, AMC 10, AMC 12, and AIME problem that uses number base — a arithmetic 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
2003 AMC 10A Problem 20 · 2013 AMC 10A Problem 19 · 2013 AMC 10B Problem 25 · 2015 AMC 10A Problem 18 · 2018 AMC 10A Problem 18 · 2019 AMC 10A Problem 18 · 2019 AMC 10B Problem 12 · 2020 AMC 10A Problem 21 · 2021 AMC 10A Spring Problem 11 · 2021 AMC 10B Spring Problem 13 · 2021 AMC 10A Fall Problem 12 · 2022 AMC 10B Problem 25 · 2024 AMC 10A Problem 18 · 2025 AMC 10B Problem 4
AMC 12
1999 AMC 12 Problem 25 · 2004 AMC 12A Problem 25 · 2005 AMC 12A Problem 19 · 2007 AMC 12B Problem 21 · 2012 AMC 12A Problem 20 · 2012 AMC 12B Problem 11 · 2013 AMC 12B Problem 23 · 2018 AMC 12A Problem 13 · 2019 AMC 12A Problem 11 · 2020 AMC 12A Problem 19 · 2021 AMC 12A Fall Problem 10 · 2022 AMC 12B Problem 23 · 2024 AMC 12A Problem 11 · 2024 AMC 12B Problem 6 · 2025 AMC 12B Problem 4
AIME
2000 AIME II Problem 14 · 2001 AIME I Problem 8 · 2003 AIME I Problem 13 · 2004 AIME II Problem 10 · 2008 AIME II Problem 4 · 2010 AIME I Problem 10 · 2012 AIME I Problem 5 · 2012 AIME II Problem 7 · 2014 AIME II Problem 15 · 2017 AIME I Problem 5 · 2017 AIME II Problem 4 · 2018 AIME I Problem 2 · 2018 AIME II Problem 3 · 2020 AIME I Problem 3 · 2020 AIME II Problem 5 · 2022 AIME I Problem 2 · 2023 AIME II Problem 2 · 2023 AIME II Problem 15 · 2024 AIME II Problem 6 · 2024 AIME II Problem 14 · 2025 AIME I Problem 1 · 2026 AIME II Problem 4