Python Exercises

Problem 1 – Python Hello World

Write a program that prints the message “Hello, World!” to the screen.

Example

hello world output

Hint

Use the print() function to display text.

Explanation

  • print() → a built-in Python function used to display output on the screen
  • "Hello, World!" → a string (text inside quotes)
  • Quotes (" ") tell Python: “this is text, not code”
  • When Python runs this line, it sends the text to the screen

👉 This is usually the first program because it shows how to display something

Solution

hello world

Problem 2 – User Input

Write a program that asks the user for their name and prints a greeting message.

Example

input name output
Hint

Use input() to get user input and print() to display the message.

Explanation

  • name → a variable (a container that stores data)
  • = → assignment operator
    • It means: “store the value on the right into the variable on the left”
  • input() → waits for the user to type something
  • "Enter your name: " → text shown to the user
  • Whatever the user types is stored inside name
  • print("Hello", name) → prints text + variable value

👉 Flow:
1. Ask user for input
2. Store it
3. Use it later

Solution
input name input

Problem 3 – Simple Addition

Write a program that asks the user for two numbers and prints their sum.

Example

simple addition output

Hint

Use input() to get values
Convert them to integers using int()

Explanation

  • input() always returns text (string)
  • int() converts text into a number (integer)
  • a and b are variables storing numbers
  • a + b → adds the numbers
  • print("Sum:", a + b) → prints label + result

👉 Important: If you don’t use int(), Python will try to join text instead of adding numbers

Solution

simple addition input

Problem 4 – Python Even or Odd

Write a program that checks if a number is even or odd.

Example

even or odd output

Hint

Use the modulus operator % to check the remainder when dividing by 2.

Explanation
% → modulus operator (returns the remainder of division)
num % 2:

  • If result = 0 → divisible by 2 → even
  • If result ≠ 0 → odd

if condition: → runs code if condition is true
else: → runs if condition is false

👉 Example:

  • 4 % 2 = 0 → even
  • 5 % 2 = 1 → odd

Solution

even or odd input

Problem 5 – Python Positive or Negative

Write a program that checks if a number is positive, negative, or zero.

Example

neg pos output

Hint

Use if, elif, and else to compare the number with 0.

Explanation
if num > 0 → checks if number is greater than zero
elif num < 0 → checks if number is less than zero
else → runs if none of the above are true
== means “equal to”
Conditions are checked top to bottom

👉 Flow:
1. Check positive
2. If not, check negative
3. If not, must be zero

Solution

neg pos input

Problem 6 – Python Print Numbers from 1 to N

Write a program that asks the user for a number N and prints all numbers from 1 to N.

Example

n number output

Hint

Use a for loop with range().

Explanation

range(1, n + 1):
starts at 1
stops before n + 1
so it prints up to n
for i in range(...):
repeats code for each number
i takes values 1, 2, 3…
print(i) → prints each number

👉 Loop = repeat action multiple times

Solution

n number input

Problem 7 – Python Sum of Numbers

Write a program that calculates the sum of numbers from 1 to N.

Example

sum of numbers output

Hint

Use a loop and keep adding values to a variable.

Explanation

  • total = 0 → starting value (important for accumulation)
  • Loop runs from 1 to n
  • total += i means:
total = total + i

Each loop adds the next number
Final value = total sum

👉 Example:
1 + 2 + 3 + 4 + 5 = 15

Solution

sum of numbers input

Problem 8 – Python Multiplication Table

Write a program that prints the multiplication table of a number from 1 to 10.

Example

multiplication output

Hint

Use a loop from 1 to 10.

Explanation

range(1, 11) → numbers from 1 to 10
n * i → multiplies the number
print() → formats the output

👉 This combines loops + arithmetic

Solution

multiplication input

Problem 9 – Python Count Digits

Write a program that counts how many digits a number has.

Example

count digits output

Hint

Divide the number by 10 repeatedly.

Explanation

1. What is a while loop?
A while loop repeats code as long as a condition is true
Here, the condition is: num > 0
So the loop keeps running until num becomes 0

👉 In simple terms:

“Keep doing this while the number is still greater than zero”

2. What does // do?
// is integer division

It divides the number and removes the decimal part

👉 Examples:

1 // 10 = 0

1234 // 10 = 123

123 // 10 = 12

12 // 10 = 1

👉 So:

Each time we divide by 10, we remove the last digit

3. What does += mean?

count +=1 is a shortcut for count = count +1

It adds 1 to the current value
Used to count how many times something happens

Full Logic Step-by-Step
Let’s say the user enter:
1234

Loop 1:
num > 0 → True
num = 1234 // 10 = 123
count = 0 + 1 = 1

Loop 2:
num = 123
num = 123 // 10 = 12
count = 2

Loop 3:
num = 12
num = 12 // 10 = 1
count = 3

Loop 4:
num = 1
num = 1 // 10 = 0
count = 4

Loop 5
num = 0 → condition is false → loop ends

Final result
4
👉 Because the number has 4 digits

Simple summary
while → repeats until condition is false

// 10 → removes one digit

+= 1 → counts how many times it happens

👉 Number of loops = number of digits

👉 “Each loop removes one digit, so counting the loops gives the total number of digits.”

Solution

count digits input

Problem 10 – Python Reverse a Number

Write a program that reverses a number.

Example

reverse output

Hint

Use % 10 to extract digits.

Explanation

num % 10 → gets last digit

  • 1234 → 4

reverse * 10 → shifts digits left
+ digit → adds new digit
num // 10 → removes last digit
Loop repeats until number is 0

👉 Example:

  • Start: 1234
  • Step 1: 4
  • Step 2: 43
  • Step 3: 432
  • Step 4: 4321

Solution

reverse input