Lesson 3 of 21 · about 5 minutes with the exercises

Variables

A variable is a name that points to a value. Once a value has a name, you can use the name again and again, and you can change the value in one place. Almost every program is built from variables.

Making a variable

Write the name, an equals sign, and the value.

name = "Asha"
age = 14
height = 1.52
print(name)
print(age)
print(height)

Output

Asha
14
1.52

The equals sign here does not mean "is equal to" as in maths. It means "take the value on the right and store it under the name on the left". Programmers call this assignment.

Notice that print(name) has no quotation marks. With quotation marks, Python would print the word name itself. Without them, it looks up what the name points to.

Changing a variable

A variable can be given a new value at any time. The old value is forgotten.

score = 10
print(score)
score = 25
print(score)
score = score + 5
print(score)

Output

10
25
30

The line score = score + 5 looks odd at first. Python works out the right side first, using the current value 25, gets 30, and then stores 30 back under the same name. This pattern is so common that there is a short form:

score = 30
score += 5
print(score)
score -= 10
print(score)

Output

35
25

Rules for names

A name can use letters, digits and the underscore _.
It cannot start with a digit. class8 is fine. 8class is not.
It cannot contain spaces. Use an underscore: total_marks.
Capital letters matter. Marks and marks are two different variables.
A few words belong to Python and cannot be used, for example if, for, class and True.

Beyond the rules, choose names that say what the value is. price_per_kg is longer than p, but a reader understands it at once. The usual Python style is small letters with underscores between words.

Types of value

Every value has a type. The four you need first are:

Type	Meaning	Example
`int`	whole number	`14`
`float`	number with a decimal point	`1.52`
`str`	text, called a string	`"Asha"`
`bool`	true or false	`True`

The type function tells you what a value is.

print(type(14))
print(type(1.52))
print(type("Asha"))
print(type(True))

Output

<class 'int'>
<class 'float'>
<class 'str'>
<class 'bool'>

A variable is not fixed to one type. It simply points to whatever you last gave it. Still, changing the kind of thing a name holds halfway through a program confuses readers, so avoid it.

Several variables in one line

You can assign more than one variable at a time. This also gives a neat way to swap two values.

x, y = 5, 9
print(x, y)
x, y = y, x
print(x, y)

Output

5 9
9 5

Using a name before it exists

Python reads from top to bottom. If you use a name before giving it a value, or you misspell it, you get a NameError.

total = 50
print(totl)

What Python says

Traceback (most recent call last):
  File "example.py", line 2, in <module>
    print(totl)
          ^^^^
NameError: name 'totl' is not defined. Did you mean: 'total'?

The message even suggests the name you probably meant. See NameError explained for more.

Try it yourself

Exercise 1. Make variables for a product name, its price and the quantity bought. Print the total cost.

Show one answer

product = "Notebook"
price = 45
quantity = 6
print(product, "total:", price * quantity)

Output

Notebook total: 270

Exercise 2. Start with runs = 0. Add 4, then add 6, then print the result. Use the short form +=.

Show one answer

runs = 0
runs += 4
runs += 6
print(runs)

Output

Exercise 3. Two variables hold a = "tea" and b = "coffee". Swap them in one line and print both.

Show one answer

a = "tea"
b = "coffee"
a, b = b, a
print(a, b)

Output

coffee tea

Examples on this page were run with Python 3.14 on 12 November 2026. The output shown is the real output.

This is an independent learning site. It is not connected with or approved by the Python Software Foundation. "Python" is a trademark of the Python Software Foundation and is used here only to name the language.