Variable assignment in Python - Mini Project: Build & Apply

Variable assignment in Python

📖 Scenario: You are helping a small bakery keep track of the number of cakes they have made today.

🎯 Goal: You will create variables to store the number of cakes made in the morning and afternoon, then calculate the total cakes made in the day.

📋 What You'll Learn

Create variables with exact names and values as instructed

Use simple addition to combine values

Print the final total number of cakes

💡 Why This Matters

🌍 Real World

Tracking daily production numbers helps businesses understand their output and plan better.

💼 Career

Variable assignment is a fundamental skill used in all programming jobs to store and manipulate data.

1

Create morning cakes variable

Create a variable called morning_cakes and set it to 15.

Python

# Create a variable called morning_cakes and set it to 15
# Your code here

Hint

Use the equals sign = to assign the value 15 to the variable morning_cakes.

2

Create afternoon cakes variable

Create a variable called afternoon_cakes and set it to 20.

Python

morning_cakes = 15
# Create a variable called afternoon_cakes and set it to 20
# Your code here

Hint

Use the equals sign = to assign the value 20 to the variable afternoon_cakes.

3

Calculate total cakes

Create a variable called total_cakes and set it to the sum of morning_cakes and afternoon_cakes.

Python

morning_cakes = 15
afternoon_cakes = 20
# Create a variable total_cakes that adds morning_cakes and afternoon_cakes
# Your code here

Hint

Use the plus sign + to add the two variables and assign the result to total_cakes.

4

Print total cakes

Write a print statement to display the value of total_cakes.

Python

morning_cakes = 15
afternoon_cakes = 20
total_cakes = morning_cakes + afternoon_cakes
# Print the total_cakes variable
# Your code here

Hint

Use print(total_cakes) to show the total number of cakes made.

Practice

1. What does the following Python statement do?
age = 25

easy

A. Prints the value 25

B. Checks if age is equal to 25

C. Stores the value 25 in the variable named age

D. Deletes the variable age

Solution

1. Step 1: Understand the assignment operator

   The = sign in Python assigns the value on the right to the variable on the left.

2. Step 2: Analyze the statement age = 25

   This means the number 25 is stored inside the variable named age.

3. Final Answer:

   Stores the value 25 in the variable named age -> Option C

4. Quick Check:

   Assignment means storing value [OK]

Hint: Remember: '=' means store value, not compare [OK]

Common Mistakes:

• Confusing '=' with '==' for comparison
• Thinking '=' prints or deletes variables
• Assuming variable names are values

2. Which of the following is the correct way to assign the value 10 to a variable named count in Python?

easy

A. count == 10

B. count := 10

C. 10 = count

D. count = 10

Solution

1. Step 1: Identify the assignment operator

   In Python, the single equals sign = is used to assign values to variables.

2. Step 2: Check each option

   count == 10 uses == which is a comparison, not assignment. 10 = count tries to assign to a value, which is invalid. count := 10 uses walrus operator := which is valid in Python 3.8+, but not standard for simple assignment. count = 10 correctly assigns 10 to count.

3. Final Answer:

   count = 10 -> Option D

4. Quick Check:

   Use '=' for assignment [OK]

Hint: Use single '=' to assign values, not '==' [OK]

Common Mistakes:

• Using '==' instead of '=' for assignment
• Trying to assign value to a number
• Confusing walrus operator with assignment

3. What will be the output of this code?

name = "Alice"
age = 30
name = "Bob"
print(name, age)

medium

A. Alice 30

B. Bob 30

C. Alice 0

D. Bob 0

Solution

1. Step 1: Trace variable assignments

   Initially, name is set to "Alice" and age to 30. Then name is reassigned to "Bob".

2. Step 2: Understand print output

   The print statement outputs the current values of name and age. Since name was changed to "Bob", and age remains 30, the output is "Bob 30".

3. Final Answer:

   Bob 30 -> Option B

4. Quick Check:

   Last assignment wins [OK]

Hint: Last value assigned to variable is what prints [OK]

Common Mistakes:

• Thinking first assignment stays unchanged
• Confusing variable names or values
• Assuming age changes without assignment

4. Identify the error in this code snippet:

5number = 10
print(5number)

medium

A. Variable names cannot start with a number

B. Missing quotes around 5number

C. Assignment operator is wrong

D. print statement syntax error

Solution

1. Step 1: Check variable naming rules

   In Python, variable names must start with a letter or underscore, not a number.

2. Step 2: Analyze the code

   The variable name 5number starts with a digit, which is invalid syntax and causes an error.

3. Final Answer:

   Variable names cannot start with a number -> Option A

4. Quick Check:

   Variable names start with letter or underscore [OK]

Hint: Variable names cannot begin with digits [OK]

Common Mistakes:

• Starting variable names with numbers
• Confusing strings with variable names
• Assuming print syntax is wrong

5. You want to swap the values of two variables a and b in Python. Which of the following is the correct way to do it?

hard

A. a, b = b, a

B. a = b
b = a

C. temp = a
b = temp
a = b

D. a = a + b
b = a - b
a = a - b

Solution

1. Step 1: Understand swapping variables

   Swapping means exchanging values so that a gets b's value and b gets a's value.

2. Step 2: Analyze each option

   a = b b = a assigns b to a, then a to b, losing original a. temp = a b = temp a = b incorrectly assigns b before a. a = a + b b = a - b a = a - b uses arithmetic swap which works but is less clear and can cause errors with non-numbers. a, b = b, a uses Python's tuple unpacking to swap values correctly and clearly.

3. Final Answer:

   a, b = b, a -> Option A

4. Quick Check:

   Use tuple unpacking for swap [OK]

Hint: Swap with a, b = b, a for clean code [OK]

Common Mistakes:

• Overwriting variables before swapping
• Using temporary variable incorrectly
• Using arithmetic swap with non-numbers