Introduction to Operations

What are operations?

Operations are actions you can perform on values and variables in your program. You can think of them as the “verbs” of programming - they tell the computer what to do with data (values and variables).

Example:

age = 25
next_year = age + 1
print(next_year)  # Output: 26

Here, + is an operation that adds two numbers together.


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Operators

An operator is a symbol that performs an operation. It’s like a mathematical symbol that tells the computer what action to take.

Examples of operators:

  • + (addition operator)
  • - (subtraction operator)
  • == (equality operator)
  • * (multiplication operator)


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Arithmetic Operations

These operations work with numbers (integers and floats):

1. Addition (+)

Adds two numbers together.

score1 = 85
score2 = 92
total = score1 + score2
print(total)  # Output: 177

2. Subtraction (-)

Subtracts one number from another.

price = 50
discount = 10
final_price = price - discount
print(final_price)  # Output: 40

3. Multiplication (*)

Multiplies two numbers.

length = 5
width = 3
area = length * width
print(area)  # Output: 15

4. Division (/)

Divides one number by another (always gives a float result).

total_cookies = 20
people = 4
cookies_per_person = total_cookies / people
print(cookies_per_person)  # Output: 5.0

5. Integer Division (//)

Divides and rounds down to the nearest whole number.

total_cookies = 23
people = 4
whole_cookies = total_cookies // people
print(whole_cookies)  # Output: 5

6. Modulo (%)

Gives the remainder after division.

total_cookies = 23
people = 4
leftover_cookies = total_cookies % people
print(leftover_cookies)  # Output: 3

7. Exponentiation (**)

Raises a number to a power.

base = 2
power = 3
result = base ** power
print(result)  # Output: 8 (2 to the power of 3)


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Comparison Operations

These operations compare values and give True or False results:

1. Equal to (==)

Checks if two values are the same.

age = 18
is_adult = age == 18
print(is_adult)  # Output: True

2. Not equal to (!=)

Checks if two values are different.

password = "secret"
is_wrong = password != "password123"
print(is_wrong)  # Output: True

3. Greater than (>)

score = 85
passed = score > 60
print(passed)  # Output: True

4. Less than (<)

temperature = 15
is_cold = temperature < 20
print(is_cold)  # Output: True

5. Greater than or equal to (>=)

age = 18
can_vote = age >= 18
print(can_vote)  # Output: True

6. Less than or equal to (<=)

speed = 50
within_limit = speed <= 60
print(within_limit)  # Output: True


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String Operations

1. Concatenation (+)

Joins strings together.

first_name = "Alice"
last_name = "Smith"
full_name = first_name + " " + last_name
print(full_name)  # Output: Alice Smith

2. Repetition (*)

Repeats a string multiple times.

laugh = "ha"
big_laugh = laugh * 3
print(big_laugh)  # Output: hahaha


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Order of Operations

Python follows mathematical order of operations (PEMDAS):

  1. Parentheses ()
  2. Exponents **
  3. Multiplication * and Division /
  4. Addition + and Subtraction -
result = 2 + 3 * 4
print(result)  # Output: 14 (not 20!)

result_with_parentheses = (2 + 3) * 4
print(result_with_parentheses)  # Output: 20


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Remember

  • Operators are symbols that perform operations
  • Use parentheses () to make your calculations clear
  • Remember that / always gives a float, even for whole number results
  • Comparison operations are useful for making decisions in your programs
  • String operations help you build messages and format text


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