Assignment and augmented assignment in Python - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to assign the value 10 to the variable x.

Python

x [1] 10

Drag options to blanks, or click blank then click option'

A=

B==

C+=

D:=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '==' which is for comparison, not assignment.

Using '+=' when you just want to assign a value.

The single equal sign = is used to assign a value to a variable in Python.

2fill in blank

medium

Complete the code to add 5 to the variable count using augmented assignment.

Python

count [1] 5

Drag options to blanks, or click blank then click option'

A=

B+=

C-=

D*=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '=' which replaces the value instead of adding.

Using '-=' which subtracts instead of adding.

The += operator adds the value on the right to the variable on the left and updates it.

3fill in blank

hard

Fix the error in the code to multiply the variable total by 3 using augmented assignment.

Python

total [1] 3

Drag options to blanks, or click blank then click option'

A*=

B*

C=

D**

Attempts:

3 left

💡 Hint

Common Mistakes

Using '*' which only multiplies but does not assign.

Using '=' which replaces the value without multiplying.

The *= operator multiplies the variable by the value and updates it.

4fill in blank

hard

Complete the code to subtract 2 from score using augmented assignment.

Python

score [1] 2

Drag options to blanks, or click blank then click option'

A=

B+=

C-=

D*=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '+=' instead of '-=' for subtraction.

Using '*' or '+=' which do not subtract.

The -= operator subtracts the value on the right from the variable on the left and updates it.

5fill in blank

hard

Fill all three blanks to create a variable new_value that adds 4 to old_value and then multiplies by 2.

Python

new_value [1] old_value [2] 4
new_value [3] 2

Drag options to blanks, or click blank then click option'

A=

B+

C*=

D*

Attempts:

3 left

💡 Hint

Common Mistakes

Using '+=' in the first line instead of '='.

Using '*' instead of '*=' in the last line.

First, assign old_value + 4 to new_value using = and +. Then multiply new_value by 2 using *=.

Practice

1.

What does the += operator do in Python?

easy

A. Adds the right value to the left variable and updates it

B. Assigns a new variable without changing the old one

C. Subtracts the right value from the left variable

D. Creates a new list from two variables

Solution

1. Step 1: Understand the meaning of +=

   The += operator adds the value on the right to the variable on the left.

2. Step 2: Recognize it updates the variable

   It changes the original variable by adding the new value to it.

3. Final Answer:

   Adds the right value to the left variable and updates it -> Option A

4. Quick Check:

   += means add and assign [OK]

Hint: Think: add then store back in same variable [OK]

Common Mistakes:

• Confusing += with simple assignment =
• Thinking += creates a new variable
• Mixing += with subtraction or multiplication

2.

Which of the following is the correct syntax to add 5 to variable x using augmented assignment?

x = 10
# Add 5 to x here

easy

A. x =+ 5

B. x += 5

C. x =+5

D. x = x +

Solution

1. Step 1: Identify correct augmented assignment syntax

   The correct syntax to add and assign is x += 5.

2. Step 2: Check other options for syntax errors

   Choices like x =+ 5 and x =+5 use incorrect operator placement; x = x + is incomplete.

3. Final Answer:

   x += 5 -> Option B

4. Quick Check:

   Use += for adding and assigning [OK]

Hint: Remember: operator before equals for augmented assignment [OK]

Common Mistakes:

• Writing =+ instead of +=
• Leaving out the value after +
• Using incomplete expressions

3.

What is the output of this code?

count = 3
count += 4
count -= 2
print(count)

medium

A. 9

B. 7

C. 3

D. 5

Solution

1. Step 1: Calculate count += 4

   Starting from 3, adding 4 gives 7.

2. Step 2: Calculate count -= 2

   Subtracting 2 from 7 gives 5.

3. Final Answer:

   5 -> Option D

4. Quick Check:

   3 + 4 - 2 = 5 [OK]

Hint: Follow each operation step-by-step [OK]

Common Mistakes:

• Adding and subtracting in wrong order
• Confusing += and -= effects
• Ignoring the initial value

4.

Find the error in this code snippet:

total = 10
total + = 5
print(total)

medium

A. TypeError because + cannot be used with int

B. NameError because total is not defined

C. SyntaxError due to space in augmented assignment

D. No error, prints 15

Solution

1. Step 1: Check augmented assignment syntax

   The operator += must not have spaces between + and =.

2. Step 2: Identify the error caused by space

   Writing + = causes a SyntaxError in Python.

3. Final Answer:

   SyntaxError due to space in augmented assignment -> Option C

4. Quick Check:

   No spaces allowed in += operator [OK]

Hint: No spaces between + and = in augmented assignment [OK]

Common Mistakes:

• Adding spaces inside augmented assignment operator
• Assuming it works like normal addition
• Ignoring syntax error messages

5.

You have a variable score = 50. You want to increase it by 10%, then subtract 5 using augmented assignments. Which code correctly does this?

score = 50
# Increase by 10%
# Subtract 5

hard

A. score *= 1.1
score -= 5

B. score += 10
score -= 5

C. score = score + 10%
score = score - 5

D. score += 0.1
score -= 5

Solution

1. Step 1: Increase score by 10%

   Multiplying by 1.1 increases the value by 10%, so score *= 1.1 is correct.

2. Step 2: Subtract 5 using augmented assignment

   Use score -= 5 to subtract 5 from the updated score.

3. Final Answer:

   score *= 1.1 score -= 5 -> Option A

4. Quick Check:

   Multiply by 1.1 then subtract 5 [OK]

Hint: Use *= for percent increase, then -= for subtraction [OK]

Common Mistakes:

• Adding 10 instead of 10%
• Using invalid syntax like 10%
• Not updating score before subtracting