Added new game: Math Rush (Addition Challenge) in Python

Author: Mojirade18

INDEX.md

@@ -105,4 +105,7 @@ By now we have 2 numbers (variables), you and computer
 - Language: Python
 
 ### 🎯 [Typing_test](./Python/typing_speed_game/)
-- Language: Python
+- Language: Python
+
+### 🧮 [Math Rush (Addition Challenge)](./Python/math_rush/)
+- Language: Python