Some Interesting Multiples of Nine: Use Your Digits to Get the Digits!
We have unraveled two neat and powerful algorithms for calculating certain multiples of nine. These discussions might make for an interesting introduction to a number theory course, or a supplemental project in calculus or advanced algebra. The mathematics involved is within a student’s grasp, and the results are quite startling.
"Some Interesting Multiples of Nine: Use Your Digits to Get the Digits!,"
Electronic Proceedings of Undergraduate Mathematics Day: Vol. 1, Article 6.
Available at: https://ecommons.udayton.edu/epumd/vol1/iss1/6