Operator precedence and evaluation order in Python - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this expression with mixed operators?

Consider the following Python expression. What will it print?

Python

result = 3 + 4 * 2 ** 2 - 5 // 2
print(result)

A 14

B 15

C 17

D 13

💡 Hint

Remember the order: exponentiation, then multiplication/division, then addition/subtraction.

Exponentiation (2 ** 2) is 4, then multiplication (4 * 4) is 16, integer division (5 // 2) is 2, so 3 + 16 - 2 = 17.

❓ Predict Output

intermediate

What is the output of this chained comparison?

What does this code print?

Python

x = 5
print(1 < x < 10)

A True

B False

C SyntaxError

D TypeError

💡 Hint

Python supports chaining comparisons like this.

The expression 1 < x < 10 checks if x is greater than 1 and less than 10 simultaneously. Since x is 5, this is True.

❓ Predict Output

advanced

What is the output of this expression with logical and bitwise operators?

What will this code print?

Python

a = 0b1010
b = 0b1100
result = a & b == 0b1000
print(result)

A True

B False

C TypeError

D SyntaxError

💡 Hint

Remember operator precedence: & has higher precedence than ==.

The expression a & b == 0b1000 is evaluated as (a & b) == 0b1000. a & b is 0b1000 (8), so the comparison is True.

❓ Predict Output

advanced

What is the output of this expression with mixed boolean and arithmetic operators?

What does this code print?

Python

x = 3
result = x > 2 and x < 5 or x == 10
print(result)

A False

B True

C SyntaxError

D TypeError

💡 Hint

Remember that 'and' has higher precedence than 'or'.

The expression is evaluated as (x > 2 and x < 5) or (x == 10). Since x is 3, x > 2 and x < 5 is True, so the whole expression is True.

❓ Predict Output

expert

What is the output of this complex expression with assignment and arithmetic?

What will this code print?

Python

x = 2
x *= 3 + 4
print(x)

A SyntaxError

B 10

C 6

D 14

💡 Hint

Remember operator precedence: '+' is evaluated before '*='.

The expression x *= 3 + 4 is evaluated as x *= (3 + 4), so x = 2 * 7 = 14.

Practice

1. Which operator has the highest precedence in the expression 3 + 4 * 2?

easy

A. Multiplication (*)

B. Addition (+)

C. Subtraction (-)

D. Division (/)

Solution

1. Step 1: Recall operator precedence rules

   Multiplication (*) has higher precedence than addition (+), subtraction (-), and division (/).

2. Step 2: Identify highest precedence operator in expression

   In 3 + 4 * 2, multiplication (*) runs before addition (+).

3. Final Answer:

   Multiplication (*) -> Option A

4. Quick Check:

   Highest precedence = Multiplication (*) [OK]

Hint: Multiplication and division run before addition and subtraction [OK]

Common Mistakes:

• Thinking addition runs before multiplication
• Ignoring operator precedence
• Assuming left to right always applies

2. Which of the following expressions is syntactically correct in Python?

easy

A. 5 + * 3

B. 4 + (3 * 2)

C. 7 / / 2

D. 8 - -

Solution

1. Step 1: Check each expression for syntax errors

   5 + * 3 has two operators in a row without operand: invalid.
   4 + (3 * 2) uses parentheses correctly and valid operators.
   7 / / 2 has double division operator which is invalid.
   8 - - ends with operator without operand: invalid.

2. Step 2: Confirm correct syntax

   Only 4 + (3 * 2) is syntactically correct: 4 + (3 * 2).

3. Final Answer:

   4 + (3 * 2) -> Option B

4. Quick Check:

   Valid syntax = 4 + (3 * 2) [OK]

Hint: Check for missing operands or extra operators [OK]

Common Mistakes:

• Using two operators in a row
• Missing parentheses around expressions
• Ending expression with an operator

3. What is the output of the following code?

result = 10 - 3 * 2 + 4 // 2
print(result)

medium

A. 5

B. 8

C. 6

D. 4

Solution

1. Step 1: Apply operator precedence and evaluate multiplication and floor division first

   3 * 2 = 6
   4 // 2 = 2

2. Step 2: Evaluate the expression left to right with addition and subtraction

   10 - 6 + 2 = 4 + 2 = 6

3. Final Answer:

   6 -> Option C

4. Quick Check:

   10 - 6 + 2 = 6 [OK]

Hint: Multiply and divide before add and subtract [OK]

Common Mistakes:

• Adding before multiplying
• Using normal division instead of floor division
• Ignoring left to right evaluation for same precedence

4. Find the error in this expression:

value = 5 + (3 * 2

medium

A. No error, expression is correct

B. Wrong operator used

C. Extra operator before 2

D. Missing closing parenthesis

Solution

1. Step 1: Check parentheses balance

   Expression has an opening parenthesis '(' but no matching closing parenthesis ')'.

2. Step 2: Identify syntax error

   Missing closing parenthesis causes syntax error in Python.

3. Final Answer:

   Missing closing parenthesis -> Option D

4. Quick Check:

   Parentheses must be balanced [OK]

Hint: Count opening and closing parentheses carefully [OK]

Common Mistakes:

• Ignoring missing parentheses
• Assuming expression is valid without closing parenthesis
• Confusing operator errors with syntax errors

5. Given the expression result = (2 + 3) * (4 - 1) ** 2 // 5, what is the value of result?

hard

A. 9

B. 15

C. 5

D. 25

Solution

1. Step 1: Evaluate parentheses and exponentiation first

   (2 + 3) = 5
   (4 - 1) = 3
   3 ** 2 = 9

2. Step 2: Multiply and then floor divide

   5 * 9 = 45
   45 // 5 = 9

3. Final Answer:

   9 -> Option A

4. Quick Check:

   Parentheses and exponent first, then multiply, then floor divide [OK]

Hint: Do parentheses and powers before multiply/divide [OK]

Common Mistakes:

• Ignoring exponentiation precedence
• Dividing before multiplying
• Not applying floor division correctly