← Python

Comments

A # character starts a comment that Python ignores when running the code

What it does: # This is a comment is valid Python comment syntax. Comments can go after code on the same line with proper spacing. The # makes the whole line a comment — Python skips it entirely. Everything after # is a comment — only the code before it runs. # input() is commented out — only the second input() actually runs. Python uses # for comments — // is used in JavaScript and other languages. # causes Python to ignore everything from that point to the end of the line. Comments are for programmers reading the code — Python ignores them.

Common mistakes: Wrong comment symbol: // should be #. Missing closing quote.

Class: _____________________ · Name: _____________________ · Date: _________

Free printable worksheet with full answer key — or add this module to a journey and assign it to your class.

🖨 Print Worksheet and Answer key of Comments (PDF)

Take this worksheet further — free with Cloodit

Each concept is reinforced from every angle — learned, then applied, then tested.

Learning

Duo

What happens to # print('Hi')?

Prints HiNothing (ignored)

Matches

❌ print('Hi') greeting

↓

Error: Missing #

Applying

Meanings

Term

# This is a comment

Meaning

# is used to explain code - Python ignores text after the #

Practice

print("Name: ")

Testing

Gaps

This gets user's name

Check Answer

Spots

1print('Hello')

2// This is a comment

Cloodit turns curriculum-aligned coding content into journeys students work through one biome at a time.

Students earn collectable badges

Over 100 of them, across seven natural biomes.

Study Buddy

Students build a real study resource

Turns their work into revision material ready for Flash Cards and Exam study.

Diamond Dash — one of Cloodit's live, competitive Sprint games

Students lock in with Sprints

Live, competitive practice for the start of the lesson or a teacher-led lesson finisher.

A Cloodit certificate of achievement, ready to personalise and print

Custom printable certificates

Honour your top performers, or encourage a student who's trying hard — ready to print in seconds.

Teach this with your class →

Quick Questions

1. What happens to # print('Hi')?

A. Prints Hi

B. Nothing (ignored) ✓

The # makes the whole line a comment — Python skips it entirely

2. What displays? print('Hello') # greeting

A. Hello ✓

B. greeting

Everything after # is a comment — only the code before it runs

3. What does # do?

A. Prints # symbol

B. Makes text a comment ✓

# starts a comment — Python ignores everything from # to the end of the line

4. Which line runs? # input() vs input()

A. Second line only ✓

B. Both lines

# input() is commented out — only the second input() actually runs

5. What displays? # 'Test'

A. Nothing ✓

B. Test

The # turns the whole line into a comment — nothing runs

Match the Pairs

print('Hi') greeting → Error: Missing #

// This is a comment → Invalid: Use # not //

# This is a comment → Valid: Comment

print('Hi') # greeting → Ok: End-of-line comment

# print('Hi') → Output: (nothing)

print('World') # test → Output: World

Key Term

# This is a comment

# is used to explain code - Python ignores text after the #

Fill in the Blanks

1. # This gets user's name input('Name: ')

2. print('Hello') # greeting message

3. # Get student details input('Age: ')

4. #Start Program print('Press Enter')

5. # This is a comment print('Test')

Spot the Error

Question 1

A print('Hello')

B // This is a comment

C input()

Line B — Wrong comment symbol: // should be #

Question 2

A # Get user name

B input('Name: ')

C print('Age: )

Line C — Missing closing quote

Question 3

A print('Hi')

B # input('Name: ')

C print 'Done'

Line C — Missing parentheses on print

Question 4

A # Student form

B print('Name: ')

C -- This is commented

D input()

Line C — Wrong comment symbol: -- should be #

Question 5

A print('Start')

B input('Data: ') // end-of-line

C print('End')

Line B — Wrong comment symbol: // should be #

For Teachers

Create a free class, add this module to a journey, and track who's stuck.

Create a free teacher account →

No credit card. No setup fee. Make a class and invite students in under three minutes.

For Students

Practice this topic interactively, track progress, and unlock badges.

Start Learning Free →

Have a class code?