The Foundations

💡

All the notes. All the examples. All in one place. The challenges prove you understand it. Solve them all and you mastered The Foundations.

▶📝 Cheatsheet

1. Print

Before you do anything, you need to see output.

python

print("Hello World")

Printing numbers

python

print(25)
print(3.99)

Printing multiple values

python

print("Name:", "Ahmed")
print("Age:", 25)

New lines and tabs

python

print("Hello\nWorld")       # prints on two lines
print("Name:\tAhmed")       # adds a tab space

2. Variables

A variable stores a value so you can use it later.

python

name = "Hodan"
print(name)                 # Hodan

Data types

python

city = "Oslo"        # str (text)
age = 22             # int (whole number)
price = 9.99         # float (decimal)
paid = True          # bool (True or False)

Change variable

python

age = 22
age = 23
print(age)           # 23

Naming rules

python

first_name = "Hodan"   # yes
1st_name = "Hodan"     # no - can't start with a number

Concatenation

python

greeting = "Hello " + name
print(greeting)        # Hello Hodan

f-strings: the better way

python

print(f"Welcome {name}, you are {age} years old")

3. User Input

Your program can ask the user for information.

python

name = input("What is your name? ")
print(f"Hello {name}")

Storing multiple inputs

python

name = input("Name: ")
city = input("City: ")
print(f"{name} lives in {city}")

Input is always a string. Even if the user types a number.

python

age = input("Enter your age: ")
print(type(age))       # <class 'str'>

Type casting: convert it to the type you need

python

age = int(input("Enter your age: "))      # whole number
price = float(input("Enter price: "))     # decimal

4. Math

Basic operators

python

10 + 3       # 13  (addition)
10 - 3       # 7   (subtraction)
10 * 3       # 30  (multiplication)
10 / 3       # 3.333 (division)

Floor division and modulo

python

10 // 3      # 3   (division without decimals)
10 % 3       # 1   (remainder)

Rounding

python

price = 10 / 3
print(round(price, 2))   # 3.33

Order of operations

python

total = 10 + 5 * 2       # 20, not 30
total = (10 + 5) * 2     # 30

5. Text & Strings

Length

python

name = "Abdifatah"
print(len(name))           # 9

Uppercase and lowercase

python

name = "ahmed"
print(name.upper())        # AHMED
print(name.lower())        # ahmed
print(name.capitalize())   # Ahmed

Replace

python

message = "I love Java"
print(message.replace("Java", "Python"))   # I love Python

Strip whitespace

python

city = "   Oslo   "
print(city.strip())        # Oslo

Slicing

python

name = "Abdifatah"
print(name[0:4])           # Abdi
print(name[0])             # A
print(name[-1])            # h

Find and count

python

text = "banana"
print(text.find("n"))      # 2
print(text.count("a"))     # 3

Summary

Category	Key Ideas
Print	print(), \n, \t
Variables	name = value, str, int, float, bool
Input	input(), int(), float()
Math	+, -, *, /, //, %, round()
Strings	.upper(), .lower(), .replace(), .strip(), len(), slicing

▶🧩 Challenges

Challenge 1: Grocery Run

Sahra has $200. She buys rice for $25, chicken for $40, bread for $8, and milk for $6. Print the total, budget, and change.

plain text

Total: $79
Budget: $200
Change: $121

Challenge 2: Gym Membership

Mahad wants to join a gym. The fee is $50 per month. He has $320. How many full months can he pay for and how much is left?

plain text

Months: 6
Remaining: $20

Challenge 3: Flight Booking

Ahmed is booking a flight for $500. The airline adds a 10% booking fee. Print the fee and the total.

plain text

Flight: $500
Fee: $50
Total: $550

Challenge 4: Greeting Card

Ask the user for their name and their friend's name. Print a greeting card. The sender's name should be in uppercase.

plain text

===================
   GREETING CARD
===================
To: Faadumo
From: AHMED
Message: Wishing you the best!
===================

Challenge 5: Name Tag

Ask the user for their full name. Print it in uppercase and lowercase. Count the total letters without the space. Show the first and last letter.

plain text

Upper: ABDIFATAH BASHI
Lower: abdifatah bashi
Letters: 14
First: A
Last: i

Challenge 6: Pizza Split

You and your friends ordered pizza. Ask for the total bill and how many people are splitting. Print what each person pays, rounded to 2 decimals.

plain text

Total bill: $85
Friends: 6
Each pays: $14.17

Challenge 7: Username Generator

Ask the user for their first name and birth year. Create a username from the first 4 letters of their name in lowercase plus their birth year.

plain text

Name: Abdifatah
Year: 1998
Username: abdi1998

Challenge 8: Coffee Receipt

Ask the user for their name and how many coffees they want. Each coffee is $5. Print a receipt with their name in uppercase and the total.

plain text

===================
   COFFEE RECEIPT
===================
Customer: HAMDA
Coffees: 3
Total: $15
===================

Challenge 9: Contact Card

Ask for a name, phone number, and email. Print a contact card. Show the name capitalized and how many characters the email has.

plain text

===================
    CONTACT CARD
===================
Name: Ahmed Yusuf
Phone: 92345678
Email: ahmed@email.com (14 characters)
===================

Challenge 10: Travel Profile

Ask the user for their name, destination, and number of days. Print a travel card with their name in uppercase, destination capitalized, and a message about the trip.

plain text

===================
   TRAVEL PROFILE
===================
Traveler: HODAN
Destination: Istanbul
Days: 7
Note: Hodan is spending 7 days in Istanbul. Bon voyage!
===================

The Foundations

💡

All the notes. All the examples. All in one place. The challenges prove you understand it. Solve them all and you mastered The Foundations.

▶📝 Cheatsheet

1. Print

Before you do anything, you need to see output.

python

print("Hello World")

Printing numbers

python

print(25)
print(3.99)

Printing multiple values

python

print("Name:", "Ahmed")
print("Age:", 25)

New lines and tabs

python

print("Hello\nWorld")       # prints on two lines
print("Name:\tAhmed")       # adds a tab space

2. Variables

A variable stores a value so you can use it later.

python

name = "Hodan"
print(name)                 # Hodan

Data types

python

city = "Oslo"        # str (text)
age = 22             # int (whole number)
price = 9.99         # float (decimal)
paid = True          # bool (True or False)

Change variable

python

age = 22
age = 23
print(age)           # 23

Naming rules

python

first_name = "Hodan"   # yes
1st_name = "Hodan"     # no - can't start with a number

Concatenation

python

greeting = "Hello " + name
print(greeting)        # Hello Hodan

f-strings: the better way

python

print(f"Welcome {name}, you are {age} years old")

3. User Input

Your program can ask the user for information.

python

name = input("What is your name? ")
print(f"Hello {name}")

Storing multiple inputs

python

name = input("Name: ")
city = input("City: ")
print(f"{name} lives in {city}")

Input is always a string. Even if the user types a number.

python

age = input("Enter your age: ")
print(type(age))       # <class 'str'>

Type casting: convert it to the type you need

python

age = int(input("Enter your age: "))      # whole number
price = float(input("Enter price: "))     # decimal

4. Math

Basic operators

python

10 + 3       # 13  (addition)
10 - 3       # 7   (subtraction)
10 * 3       # 30  (multiplication)
10 / 3       # 3.333 (division)

Floor division and modulo

python

10 // 3      # 3   (division without decimals)
10 % 3       # 1   (remainder)

Rounding

python

price = 10 / 3
print(round(price, 2))   # 3.33

Order of operations

python

total = 10 + 5 * 2       # 20, not 30
total = (10 + 5) * 2     # 30

5. Text & Strings

Length

python

name = "Abdifatah"
print(len(name))           # 9

Uppercase and lowercase

python

name = "ahmed"
print(name.upper())        # AHMED
print(name.lower())        # ahmed
print(name.capitalize())   # Ahmed

Replace

python

message = "I love Java"
print(message.replace("Java", "Python"))   # I love Python

Strip whitespace

python

city = "   Oslo   "
print(city.strip())        # Oslo

Slicing

python

name = "Abdifatah"
print(name[0:4])           # Abdi
print(name[0])             # A
print(name[-1])            # h

Find and count

python

text = "banana"
print(text.find("n"))      # 2
print(text.count("a"))     # 3

Summary

Category	Key Ideas
Print	print(), \n, \t
Variables	name = value, str, int, float, bool
Input	input(), int(), float()
Math	+, -, *, /, //, %, round()
Strings	.upper(), .lower(), .replace(), .strip(), len(), slicing

▶🧩 Challenges

Challenge 1: Grocery Run

Sahra has $200. She buys rice for $25, chicken for $40, bread for $8, and milk for $6. Print the total, budget, and change.

plain text

Total: $79
Budget: $200
Change: $121

Challenge 2: Gym Membership

Mahad wants to join a gym. The fee is $50 per month. He has $320. How many full months can he pay for and how much is left?

plain text

Months: 6
Remaining: $20

Challenge 3: Flight Booking

Ahmed is booking a flight for $500. The airline adds a 10% booking fee. Print the fee and the total.

plain text

Flight: $500
Fee: $50
Total: $550

Challenge 4: Greeting Card

Ask the user for their name and their friend's name. Print a greeting card. The sender's name should be in uppercase.

plain text

===================
   GREETING CARD
===================
To: Faadumo
From: AHMED
Message: Wishing you the best!
===================

Challenge 5: Name Tag

Ask the user for their full name. Print it in uppercase and lowercase. Count the total letters without the space. Show the first and last letter.

plain text

Upper: ABDIFATAH BASHI
Lower: abdifatah bashi
Letters: 14
First: A
Last: i

Challenge 6: Pizza Split

You and your friends ordered pizza. Ask for the total bill and how many people are splitting. Print what each person pays, rounded to 2 decimals.

plain text

Total bill: $85
Friends: 6
Each pays: $14.17

Challenge 7: Username Generator

Ask the user for their first name and birth year. Create a username from the first 4 letters of their name in lowercase plus their birth year.

plain text

Name: Abdifatah
Year: 1998
Username: abdi1998

Challenge 8: Coffee Receipt

Ask the user for their name and how many coffees they want. Each coffee is $5. Print a receipt with their name in uppercase and the total.

plain text

===================
   COFFEE RECEIPT
===================
Customer: HAMDA
Coffees: 3
Total: $15
===================

Challenge 9: Contact Card

Ask for a name, phone number, and email. Print a contact card. Show the name capitalized and how many characters the email has.

plain text

===================
    CONTACT CARD
===================
Name: Ahmed Yusuf
Phone: 92345678
Email: ahmed@email.com (14 characters)
===================

Challenge 10: Travel Profile

Ask the user for their name, destination, and number of days. Print a travel card with their name in uppercase, destination capitalized, and a message about the trip.

plain text

===================
   TRAVEL PROFILE
===================
Traveler: HODAN
Destination: Istanbul
Days: 7
Note: Hodan is spending 7 days in Istanbul. Bon voyage!
===================