# www.khanacademy.org

 Random Link ¯\_(ツ)_/¯ Jan 2, 2022 » Modular Arithmetic 4 min; updated Jan 10, 2022 Main resource: . What is Modular Arithmetic? Where $$A$$ and $$B$$ are integers, we can write: $$\frac{A}{B} = Q \text{ remainder } R$$ Using the same $$A, B, Q, \text{ and } R$$ as above, we have: $$A \text{ mod } B = R$$ $$A \text{ mod } B$$ can be visualized as taking $$A$$ steps on a clock that runs from $$0$$ to $$B-1$$. If the number is positive we step clockwise, if it’s negative we step counterclockwise.... Jan 7, 2022 » 019. Counting Sundays 6 min; updated Jan 7, 2022 Problem Statement You are given the following information, but you may prefer to do some research for yourself: 1 Jan 1900 was a Monday. Thirty days has September, April, June and November. All the rest have thirty-one, Saving February alone, Which has twenty-eight, rain or shine. And on leap years, twenty-nine. A leap year occurs on any year evenly divisible by 4, but not on a century unless it is divisible by 400....