Python basics – Day 03

Day 3 – Operators

Project: Build a “Smart Grade Calculator”

01. Learning Goal

By the end of this lesson, you will be able to:

• Use Python’s arithmetic, comparison, and logical operators
• Understand operator precedence
• Combine operators to create expressions
• Build a small project that evaluates pass/fail and excellence

02. Problem Scenario

You are designing a simple “Smart Grade Calculator”.

The program will calculate total points, compare grades, and determine if a student passes or is excellent using logical operators.

03. Step 1 – Arithmetic Operators

Used for basic mathematical operations.

Example:

a = 7
b = 3
print(a + b)   # 10
print(a / b)   # 2.333...
print(a // b)  # 2
print(a % b)   # 1
print(a ** b)  # 343

04. Step 2 – Comparison Operators

Used to compare values. The result is always True or False.

Example:

x = 10
y = 20
print(x == y)  # False
print(x != y)  # True
print(x < y)   # True

05. Step 3 – Logical Operators

Used to combine multiple conditions.

Example:

age = 25
is_student = False

print(age > 18 and is_student)  # False (one is False)
print(age > 18 or is_student)   # True (one is True)
print(not is_student)           # True (negation)

06. Step 4 – Operator Precedence

Operations are executed in the following order:
Multiplication / Division → Addition / Subtraction
Use parentheses ( ) to control order.

print(2 + 3 * 4)      # 14 (multiplication first)
print((2 + 3) * 4)    # 20 (parentheses first)

07. Step 5 – Practice Examples

Example 1: Arithmetic Practice

x = 15
y = 4
print("Quotient:", x // y)
print("Remainder:", x % y)
print("Power:", x ** y)

Example 2: Comparison Practice

temperature = 30
print("Is it hot?", temperature > 25)
print("Is it cold?", temperature < 10)

Example 3: Logical Practice

score = 85
is_pass = score >= 60
is_excellent = score >= 90

print("Passed?", is_pass)
print("Excellent?", is_excellent)
print("Pass & Excellent?", is_pass and is_excellent)

08. Step 6 – Mini Project: Smart Grade Calculator

Build a program that evaluates a student’s performance.

name = "Sabin"
score = 88

print(f"Student: {name}")
print("Passed?", score >= 60)
print("Excellent?", score >= 90)
print("Pass but not Excellent?", score >= 60 and score < 90)

09. Reflection

You have learned how to:

• Perform mathematical operations
• Compare and combine logical conditions
• Understand operator precedence
• Build a simple Smart Grade Calculator

This knowledge is essential for decision-making logic you’ll use in conditionals, loops, and full applications later.