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AMC digits & number bases problems

Digit manipulation, place value, number bases, palindromes and repeating decimals.

155 problems in the archive use these ideas — 85 from the AMC 10 and 70 from the AMC 12.

Picks a problem you have not seen, at about the difficulty you are handling.

60 most recent problems

Newest contests first. Every problem opens with its answer choices, hints and a worked solution.

Use Start digits & number bases practice above to keep going through the remaining 95, or browse them by contest in the AMC 12 and AMC 10 archives.

Back to all number theory problems.