@sincereseagull This is a great observation! 🙂 There definitely exist negative remainders, and they are incredibly useful when we want to find the remainder of a product of numbers that are multiplied together. Prof. Loh covers negative remainders in Day 1 Challenge Part 7, Day 1 Your Turn Part 2, Day 3 Your Turn Part 3, and Day 4 Challenge Part 4. 🎉