Waste less time on Facebook — follow Brilliant.
Back to all chapters

Basic Applications of Modular Arithmetic

Solve integer equations, determine remainders of powers, and much more with the power of Modular Arithmetic.

Friday the 13th


How many days after January 13th is February 13th?

Note: January has 31 days.

If January 13 is a Monday, what day of the week is February 13?

If May 13 is a Friday, what day of the week (during the same year) is April 13?

If a non-leap year begins on a Monday, will it have a Friday the 13th?

If July 13 is a Friday, is August 13 a Friday?


Problem Loading...

Note Loading...

Set Loading...