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Phone Codes

Number Theory Level 3

The phone codes 2153, 4387, and 7738 each give the same remainder when divided by a fourth four-digit code. What is the fourth phone code?

Excel in math and science

Master concepts by solving fun, challenging problems.

It's hard to learn from lectures and videos

Learn more effectively through short, conceptual quizzes.

Our wiki is made for math and science

Master advanced concepts through explanations,
examples, and problems from the community.

Used and loved by 4 million people

Learn from a vibrant community of students and enthusiasts,
including olympiad champions, researchers, and professionals.

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by Brian Dela Torre

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