Understanding Expressions

Estimated time needed: 10 minutes

Objectives

After completing this lab you will be able to:

• Understand expressions in Python
• Declare and use variables
• Perform arithmetic operations

Table of Contents

• Expressions
• Arithmetic Operations
• Variables
• Variable Assignment and Overwriting
• Variable Types and Naming
• Summary

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Expressions

Expressions are the building blocks of Python computations.

# Basic arithmetic
100 + 60

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Arithmetic Operations

You can perform arithmetic using operators like +, -, *, /, and //.

# Subtraction
25 - 50

# Multiplication
-10 * 2.5

# Division
25 / 5
25 / 6

# Integer Division
25 // 6

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Variables

You can assign values to variables using the assignment operator =.

my_variable = 1
print(my_variable)

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Variable Assignment and Overwriting

A variable's value can be changed by reassigning it.

x = 10
x = 5 + 3
y = x / 3
x = y

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Variable Types and Naming

Check variable types using type() and use meaningful variable names.

type(x)
total_min = 142
total_hour = total_min / 60

# Update input variable and see final result update
total_min = 200
total_hour = total_min / 60

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Summary

• Expressions combine values and operators to compute results
• Variables store values for reuse and manipulation
• Python follows mathematical precedence in operations
• Meaningful variable names improve code clarity

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