CodeHS: Introduction to Programming Assignments (Python) with complete verified solutions 2025

1.2.2 Quiz: Karel Commands

Question: 1

Which of these is a valid Karel command?

move

MOVE

move()

move(1)

Question: 2

Which one of these is NOT a command that Karel knows?

Turn Left

Turn Right

Move Forward

Put Down a Ball

move()

Turn Right

1.2.4: Your First Karel Program

if front_is_clear():

move()

if balls_present():

take_ball()

else:

move()

if front_is_clear():

move()

if balls_present():

take_ball()

else:

move()

if balls_present():

take_ball()

1.2.5: Short Stack

move()

put_ball()

put_ball()

move()

1.3.2 More Basic Karel Quiz

Question: 1

What is a street in a Karel world?

A row

A column

A single point

Karel's position

Question: 2

What is an avenue in a Karel world?

A row

A column

A single point

Karel's position

Question: 3

If Karel starts at Street 1 and Avenue 3 facing East, what street (row) and avenue (column) will Karel be on after this code runs?

move()

move()

move()

turn_left()

move()

Street 1 and Avenue 3

Street 4 and Avenue 4

Street 2 and Avenue 6

Street 6 and Avenue 2

Question: 4

If Karel is facing North and the code

turn_left()

turn_left()

runs, which direction is Karel facing now?

North

South

East

West

A row

A column

Street 2 and Avenue 6

South

1.3.4: Make a Tower

move()

turn_left()

put_ball()

move()

put_ball()

move()

put_ball()

move()

turn_left()

turn_left()

turn_left()

1.3.5: Pyramid of Karel

put_ball()

move()

put_ball()

move()

turn_left()

put_ball()

move()

put_ball()

turn_left()

move()

put_ball()

turn_left()

turn_left()

move()

turn_left()

move()

put_ball()

turn_left()

turn_left()

turn_left()

1.4.2 Karel Can't Turn Right Quiz

Question: 1

How many times should Karel turn left in order to turn right?

1

2

3

4

Question: 2

What can be used to teach Karel to turn right?

Functions

Variables

Dog treats

Karel can already turn right

3

Functions

1.4.4: Fireman Karel

def turn_right():

turn_left()

turn_left()

turn_left()

turn_right()

move()

move()

move()

turn_left()

1.4.5: Slide Karel

def turn_right():

turn_left()

turn_left()

turn_left()

put_ball()

move()

turn_right()

move()

put_ball()

move()

turn_left()

move()

put_ball()

1.5.2 Functions in Karel Quiz

Question: 1

Which function will teach Karel how to spin in a circle one time?

A

def spin():

turn_right()

B

def spin():

turn_left()

turn_left()

turn_left()

turn_left()

C

def spin():

turn_left()

turn_left()

D

def spin():

move()

move()

move()

move()

A

B

C

D

B

1.5.4: Pancakes

def make_pancakes():

put_ball()

put_ball()

put_ball()

move()

make_pancakes()

move()

move()

make_pancakes()

move()

move()

make_pancakes()

move()

1.5.5: Backflip

def backflip():

turn_left()

turn_left()

turn_left()

turn_left()

move()

move()

move()

move()

backflip()

1.5.6: Digging Karel

def turn_right():

turn_left()

turn_left()

turn_left()

def turn_around():

turn_left()

turn_left()

def bury_ball():

turn_right()

move()

move()

move()

put_ball()

turn_around()

move()

move()

move()

turn_right()

move()

move()

bury_ball()

move()

move()

move()

bury_ball()

move()

move()

move()

bury_ball()

move()

1.6.2 Top Down Design and Decomposition Quiz

Question: 1

Why do we use functions in programming?

Break down our program into smaller parts

Avoid repeating code

Make our program more readable

All of the above

Question: 2

What is top down design?

Top down design is a way of designing your program by starting with the biggest problem and breaking it down into smaller and smaller pieces that are easier to solve.

Top down design is a way that you can create designs on a computer to put on a web page

Top down design is a way of designing your programs starting with the individual commands first

Top down design is a way to use loops and classes to decompose the problem

All of the above

Top down design is a way of designing your program by starting with the biggest problem and breaking it down into smaller and smaller pieces that are easier to solve.

1.6.4: The Two Towers

def stack():

put_ball()

turn_left()

move()

put_ball()

move()

put_ball()

turn_twice()

move()

move()

turn_left()

def turn_twice():

turn_left()

turn_left()

def turn_right():

turn_left()

turn_left()

turn_left()

move()

stack()

move()

move()

turn_left()

put_ball()

move()

put_ball()

move()

put_ball()

move()

turn_right()

1.7.2 Commenting Your Code Quiz

Question: 1

What is a code comment?

A way to teach Karel a new word

A way to give notes to the reader to explain what your code is doing

A message to your teacher in code

A place to write whatever you want in your code

A way to give notes to the reader to explain what your code is doing

1.7.4: The Two Towers + Comments

def stack():

put_ball()

turn_left()

move()

put_ball()

move()

put_ball()

turn_twice()

move()

move()

turn_left()

def turn_twice():

turn_left()

turn_left()

def turn_right():

turn_left()

turn_left()

turn_left()

move()

# make a stack of 3 balls

stack()

move()

move()

turn_left()

# starting a stack of 3 balls

put_ball()

move()

put_ball()

move()

put_ball()

move()

turn_right()

1.8.2 Abstraction Quiz

Question: 1

Each of the following answer choices describes a basketball game.

Which answer choice describes the game with the lowest level of abstraction?

The Warriors won by 10 points.

The Warriors had an early lead, but were down by 4 at halftime. They tied it up in the 4th quarter and the game went into overtime. They won by 10 points in overtime.

First, Steph Curry jumped in the air and grabbed the ball. Then he dribbled it three times and passed it to Klay Thompson...

First, Steph Curry flexed his left and right quad muscles at the exact same time, then he flexed each muscle in his fingers...

Question: 2

Karel needs to pick up a pile of tennis balls.

Which of the following program functions solves the problem at the highest level of abstraction?

move()

move()

turn_left()

turn_left()

turn_left()

move()

take_ball()

take_ball()

move_twice()

turn_left()

turn_left()

turn_left()

move()

take_pile()

move_twice()

turn_right()

move()

take_pile()

move_to_pile()

take_pile()

First, Steph Curry flexed his left and right quad muscles at the exact same time, then he flexed each muscle in his fingers...

move_to_pile()

take_pile()

1.9.2 Super Karel Quiz

Question: 1

What commands does SuperKarel know that regular Karel does not?

turn_left() and jump()

turn_right() and jump()

turn_around() and turn_right()

turn_around() and jump()

turn_around() and turn_right()

1.9.4: The Two Towers + SuperKarel

def stack():

put_ball()

turn_left()

move()

put_ball()

move()

put_ball()

turn_around()

move()

move()

turn_left()

move()

# make a stack of 3 balls

stack()

move()

move()

turn_left()

# starting a stack of 3 balls

put_ball()

move()

put_ball()

move()

put_ball()

move()

turn_right()

1.10.2 For Loops Quiz

Question: 1

What is the best way for Karel to move 10 times?

move()

move()

move()

move()

move()

move()

move()

move()

move()

move()

for i in range(10):

move()

move(10)

move10()

for i in range(10):

move()

1.10.5: Take 'em All

move()

for i in range(100):

take_ball()

move()

1.10.6: Dizzy Karel

for i in range(32):

turn_left()

1.10.7: For Loop Square

for i in range(4):

put_ball()

move()

turn_left()

1.10.8: Lots of Hurdles

def jump_hurdle():

turn_left()

move()

turn_right()

move()

turn_right()

move()

turn_left()

for i in range(5):

move()

move()

jump_hurdle()

1.11.2 If Statements Quiz

Question: 1

Why do we use if statements in Python?

To break out of some block of code

To do something only if a condition is true

To do something while a condition is true

To repeat something for a fixed number of times

Question: 2

Which general if statement definition is written correctly?

A

for condition: # code

B

if condition: # code

C

if i in range(COUNT): #code

D

if false: # code

A

B

C

D

To do something only if a condition is true

B

1.11.5: Is There a Ball?

if no_balls_present():

put_ball()

move()

1.12.2 If/Else Statements Quiz

Question: 1

What does an if/else statement look like in Python?

if condition:

# code

if condition:

# code

else condition:

# code

if condition:

# code

if condition:

# code

if condition:

# code

else:

# code

Question: 2

Why do we use if/else statements in Python?

To repeat something for a fixed number of times

To do something if a condition is true and do something else if the condition is false

To break out of some block of code

To repeat something while a condition is true

if condition:

# code

else:

# code

To do something if a condition is true and do something else if the condition is false

1.12.5: Right Side Up

if facing_south():

turn_left()

if facing_west():

turn_left()

turn_left()

1.13.2 While Loops in Karel Quiz

Question: 1

Why do we use while loops in Python?

To break out of some block of code

To do something if a condition is true

To repeat some code while a condition is true

To repeat something for a fixed number of times

Question: 2

Which general while loop definition is written correctly?

while x is true:

# code

if i<5:

#code

while I in range(5):

# code

while condition:

# code

To repeat some code while a condition is true

while condition:

# code

1.13.4: Follow The Yellow Ball Road

while balls_present():

move()

1.13.5: Lay Row of Tennis Balls

put_ball()

while balls_present():

move()

put_ball()

1.13.6: Big Tower

put_ball()

if facing_west():

turn_right()

if facing_south():

turn_left()

turn_left()

if facing_east():

turn_left()

while front_is_clear():

move()

put_ball()

1.14.2 Control Structures Example Quiz

Question: 1

What do we use control structures for in Python?

Control the flow of the program; how the commands execute.

Start our Python program

Store information for later

Teach Karel new commands

Question: 2

Which of the below are examples of control structures?

(I) if

(II) if/else

(III) while

(IV) for

I only

I and II only

III and I only

I, II, III, and IV

Control the flow of the program; how the commands execute.

I, II, III, and IV

1.14.4: Random Hurdles

def jump_hurdle():

turn_left()

move()

turn_right()

move()

turn_right()

move()

turn_left()

for i in range(13):

if front_is_clear():

move()

else:

jump_hurdle()

1.15.2 Debugging Basics

Question: 1

Will the following program move Karel one space, put down three tennis balls, then move forward and put down three more tennis balls?

def tennis_balls():

for i in range(3):

if no_balls_present():

put_ball()

else: take_ball()

move()

tennis_balls()

move()

tennis_balls()

Yes, because it is using the tennis_balls() function.

No, because the tennis_balls() function is looping the wrong number of times.

Yes, because the move() command is being called outside of the function.

No, because the tennis_balls() function has an incorrect if/else statement.

Question: 2

The following code contains an error. What line is it on?

1 def turn_right():

2 turn_left()

3 turn_left()

4 turn_Left()

5

6 move()

7 turn_left()

8 move()

9 turn_right()

10 move()

11 move()

line 3

line 4

line 5

line 7

No, because the tennis_balls() function has an incorrect if/else statement.

line 4

1.15.6 Debugging with Error Messages

Question: 1

Which of the following is an example of a 'runtime error'?

I. Karel crashing into a wall

II. Leaving a colon off the end of a function definition

III. Using the wrong syntax in an if/else statement

IV. Not closing all open parenthesis

I

I and III

II and IV

I-IV, all

Question: 2

If the following program is supposed to put down three tennis balls, where is the logic error?

1 def place_three_ball():

2 for i in range(4):

3 put_ball()

4

5 placeThreeBalls()

Line 1

Line 2

Line 3

Line 5

I

Line 2

1.16.2 Quiz: Which Control Structure?

Question: 1

You need to write a program where Karel will take a ball if there is a ball present, otherwise Karel should put down a ball.

Which control structure do you need to use?

For Loop

While Loop

If Statement

If/Else statement

None of these

Question: 2

You need to write a program that has Karel move 6 times and then put a ball.

Which control structure do you need to use?

For loop

While Loop

If Statement

If/Else statement

None of these

Question: 3

You need to write a program that has Karel take all the tennis balls if there are any where Karel is standing.

Karel should end up with no tennis balls on that spot.

Which control structure do you need to use?

For Loop

While Loop

If Statement

If/Else Statement

None of these

Question: 4

You need to write a program that has Karel put down a tennis ball if the world has dimensions of 1x1.

Which control structure do you need to use?

For Loop

While Loop

If Statement

If/Else statement

None of these

Question: 5

You need to write a program that has Karel move one time if the front is clear, but if it isn't clear, Karel will do nothing.

Which control structure do you need to use?

For Loop

While Loop

If Statement

If/Else statement

None of these

If/Else statement

For loop

While Loop

If Statement

If Statement

1.16.6: Decorate the Fence

while front_is_clear():

move()

def stack():

if front_is_blocked():

put_ball()

turn_left()

move()

turn_right()

else:

turn_left()

move()

turn_right()

for i in range(9):

stack()

put_ball()

turn_left()

1.17.2 Ultra Karel Quiz

Question: 1

Which of the following is the correct way to have Karel paint a red square using the paint function?

paint_red()

paint_color.red()

paint(color["red"])

paint(color[red])

Question: 2

What is a parameter?

Another name for a function

Input into a function

Output from a function

A function that paints a square in Karel's grid world

paint(color["red"])

Input into a function

1.17.5: Invert Colors

def invert_color():

if color_is(color["red"]):

paint(color["blue"])

move()

if color_is(color["blue"]):

paint(color["red"]

move()

while front_is_clear():

invert_color()

if front_is_blocked():

if color_is(color["red"]):

paint(color["blue"])

else:

paint(color["red"])

1.17.6: Checkerboard Karel

for i in range(8):

while front_is_clear():

paint(color['black'])

move()

paint(color['red'])

if front_is_clear():

move()

while not_facing_north():

turn_left()

if front_is_clear():

move()

if right_is_blocked():

turn_left()

if left_is_blocked():

turn_right()

turn_around()

while front_is_clear():

move()

turn_left()

1.18.1: Fetch

turn_left()

for i in range(4):

move()

turn_right()

move()

move()

take_ball()

turn_left()

turn_left()

move()

move()

for i in range(3):

turn_right()

for i in range(4):

move()

turn_left()

put_ball()

1.18.2: Racing Karel

for i in range(32):

while front_is_clear():

move()

while front_is_blocked():

turn_left()

put_ball()

1.18.3: Tower Builder

def tower():

turn_left()

put_ball()

move()

put_ball()

move()

put_ball()

turn_around()

move()

move()

turn_left()

tower()

while front_is_clear():

move()

if front_is_clear():

move()

tower()

1.18.4: Super Cleanup Karel

for i in range(30):

while front_is_clear():

if balls_present():

take_ball()

move()

else:

move()

while not_facing_north():

turn_left()

if balls_present():

take_ball()

if front_is_clear():

move()

if right_is_blocked():

turn_left()

if left_is_blocked():

turn_right()

1.18.5: Double Tennis Balls

move()

while balls_present():

take_ball()

move()

put_ball()

put_ball()

turn_around()

move()

turn_around()

move()

turn_around()

while balls_present():

take_ball()

move()

put_ball()

turn_around()

move()

turn_around()

move()

move()

turn_around()