Try This Number Theory Problem

Number Theory Level 1

An integer is a multiple of 9 if the sum of its digits is a multiple of 9. In the above example, we know that \(135\) is a multiple of 9 because \( 1 + 3 + 5 = 9 \) is a multiple of 9.

Which of the following numbers is a multiple of 9?

Courses

Topics

Community

100 Day Summer Challenge

Try This Number Theory Problem

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.

Courses

Topics

Community

100 Day Summer Challenge

Try This Number Theory Problem

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.

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

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

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

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