Adaptive Lesson
The difficulty adapts to your mastery in real time.
A variable is a named reference to a value stored in memory. In Python you don't declare a type — the interpreter infers it from the value you assign.
The core built-in types are int, float, str, bool, list, dict, tuple, and set. Each behaves differently when you operate on it. Knowing which type you're holding lets you predict what an operation will do.
Mutability matters: lists and dicts can change in place, while strings and tuples cannot. This single distinction explains a surprising number of bugs.
score = 95 # int name = "Ada" # str passed = score >= 60 # bool -> True grades = [95, 88] # list (mutable) grades.append(72) # [95, 88, 72]
Try predicting the type of each variable before running it — that habit is what mastery looks like.
Difficulty
Current difficulty: Medium
Reach 85% to unlock Mastery difficulty and the next mission.
Next: Control Flow & Loops
PathFinder AI suggests this once you pass the challenge.