Python Variables & Types — With an AI Explainer Beside You

In Python, you create a variable by typing a name, an equals sign, and a value. Python figures out the type automatically. That is both its magic and its trap — the moment you mix types wrong, it yells.

# The four types you will use every day
name = "Maya"          # str  (text)
age = 13                # int  (whole number)
height_m = 1.58         # float (decimal)
is_student = True       # bool (True or False)

print(f"{name} is {age} years old.")
print(f"Type of age: {type(age).__name__}")

Typecasting: turning one type into another

user_input = input("Your age? ")   # input() always returns str
age = int(user_input)              # cast to int for math
next_year = age + 1
print(f"Next year you'll be {next_year}.")

# The classic bug: forgetting to cast
bad = user_input + 1   # TypeError: can only concatenate str (not "int") to str

Mini-exercise

1. 1Create variables for: your first name, your age, your favorite decimal number, and whether you like pineapple on pizza
2. 2Print a sentence using an f-string that uses all four
3. 3Deliberately cause a TypeError by adding a str to an int
4. 4Paste the error into your AI assistant and ask it to explain

Big idea: Python infers types so you write less, but mistyped values still blow up. Pair every new variable with a quick 'what type is this?' check in your head — and if you cannot tell, ask your AI.