diff --git a/DAS/Arithmetic.md b/DAS/Arithmetic.md
index 87e3d41..254a1c6 100644
--- a/DAS/Arithmetic.md
+++ b/DAS/Arithmetic.md
@@ -33,5 +33,9 @@ Result is the last $"Remainder"$ that is not $0$.
 3. **Simplify** (Final Form: $"GCD" = x * "Dividend" + "y * Divisor"$)
 
 ### Extended Euclidian Algorithm
+Only valid for GCD = 1
+
 1. **Find GCD** using Euclidian Algorithm
-2. 
\ No newline at end of file
+	1. $A = q_1 * B + r_1$
+	2. $B = q_2 * r_1 + r_2$
+	3. $r_1 = q_3 * r_2 + 1$