6120a Discrete Mathematics And Proof For Computer Science Fix //top\\

If you see ax ≡ 1 (mod n) , you need an inverse. It exists iff gcd(a,n) = 1 . Use the Extended Euclidean Algorithm. Don’t guess. Practice it until mechanical.

Discrete math is highly visual. If you’re studying , draw the vertices and edges. If you’re stuck on Set Theory , use Venn diagrams. Turning abstract notation into a physical sketch often reveals the "logical leak" in your understanding. Use the "Code Translation" Method If you see ax ≡ 1 (mod n) , you need an inverse