***

## 🧮 1. Print Numbers from 1 to 10

**Problem:**
Print numbers from 1 to 10 using a `for` loop.

**Example Output:**

```
1
2
3
4
5
6
7
8
9
10

```

**Solution:**

```
for i in range(1, 11):
    print(i)

```

**Explanation:**
`range(1, 11)` generates numbers from 1 to 10.
The `for` loop prints each number one by one.

***

## 🔢 2. Sum of First N Natural Numbers

**Problem:**
Calculate the sum of numbers from 1 to N.

**Example Input:**

```
N = 5

```

**Example Output:**

```
15

```

**Solution:**

```
N = 5
total = 0
for i in range(1, N + 1):
    total += i
print(total)

```

**Explanation:**
We initialize a variable `total` and keep adding each number in every loop cycle.

***

## ⭐ 3. Print Each Character in a String

**Problem:**
Print each character of a string using a `for` loop.

**Example Input:**

```
Python

```

**Example Output:**

```
P
y
t
h
o
n

```

**Solution:**

```
word = "Python"
for char in word:
    print(char)

```

**Explanation:**
Strings are iterable — the loop automatically picks each character one by one.

***

## 🧾 4. Print Even Numbers from 1 to 20

**Problem:**
Print only even numbers between 1 and 20.

**Example Output:**

```
2 4 6 8 10 12 14 16 18 20

```

**Solution:**

```
for i in range(2, 21, 2):
    print(i, end=" ")

```

**Explanation:**
The third argument in `range(start, stop, step)` controls the increment.
Here, we step by 2 to get only even numbers.

***

## 💬 5. Print List Elements Using Loop

**Problem:**
Display all elements from a list using a loop.

**Example Input:**

```
fruits = ["apple", "banana", "cherry"]

```

**Example Output:**

```
apple
banana
cherry

```

**Solution:**

```
fruits = ["apple", "banana", "cherry"]
for fruit in fruits:
    print(fruit)

```

**Explanation:**
Looping over a list gives you each element directly — no index needed.

***

## 🔄 6. Reverse Counting from 10 to 1

**Problem:**
Print numbers from 10 down to 1.

**Example Output:**

```
10 9 8 7 6 5 4 3 2 1

```

**Solution:**

```
for i in range(10, 0, -1):
    print(i, end=" ")

```

**Explanation:**
Using a **negative step value** in `range()` helps count backward.

***

## ⏳ 7. Print Multiplication Table of a Number

**Problem:**
Take a number and print its multiplication table up to 10.

**Example Input:**

```
n = 3

```

**Example Output:**

```
3 x 1 = 3
3 x 2 = 6
...
3 x 10 = 30

```

**Solution:**

```
n = 3
for i in range(1, 11):
    print(f"{n} x {i} = {n * i}")

```

**Explanation:**
We multiply `n` by each `i` in range 1–10 and print the result.

***

## 🧠 8. Find the Factorial of a Number

**Problem:**
Find factorial of a number (e.g., 5! = 1×2×3×4×5).

**Example Input:**

```
5

```

**Example Output:**

```
120

```

**Solution:**

```
n = 5
fact = 1
for i in range(1, n + 1):
    fact *= i
print(fact)

```

**Explanation:**
Multiply all numbers from 1 to n sequentially to find the factorial.

***

## 🔁 9. Print Digits of a Number (Using while loop)

**Problem:**
Display each digit of a number separately.

**Example Input:**

```
1234

```

**Example Output:**

```
4
3
2
1

```

**Solution:**

```
num = 1234
while num > 0:
    digit = num % 10
    print(digit)
    num //= 10

```

**Explanation:**
Use modulo `%` to extract the last digit and integer division `//` to remove it.

***

## 🎮 10. FizzBuzz (Classic Loop Problem)

**Problem:**
Print numbers 1–20 but:

* Print “Fizz” if divisible by 3
* Print “Buzz” if divisible by 5
* Print “FizzBuzz” if divisible by both

**Example Output:**

```
1
2
Fizz
4
Buzz
Fizz
7
8
Fizz
Buzz
11
Fizz
13
14
FizzBuzz
...

```

**Solution:**

```
for i in range(1, 21):
    if i % 3 == 0 and i % 5 == 0:
        print("FizzBuzz")
    elif i % 3 == 0:
        print("Fizz")
    elif i % 5 == 0:
        print("Buzz")
    else:
        print(i)

```

**Explanation:**
Conditions are checked in order.
If both 3 and 5 divide the number, print `"FizzBuzz"` first — otherwise the correct single case.



### 🧮 11. Sum of Even Numbers in a List

**Problem:** Calculate the sum of all even numbers in a given list.
**Example Input:**

```
numbers = [1, 4, 7, 10, 12]

```

**Output:**

```
26

```

```
numbers = [1, 4, 7, 10, 12]
total = 0
for num in numbers:
    if num % 2 == 0:
        total += num
print(total)

```

**Explanation:** Loop over each number; if divisible by 2, add to `total`.

***

### 🔢 12. Count Vowels in a String

**Problem:** Count the number of vowels in a string.
**Input:** `"Python is fun"`
**Output:** `4`

```
text = "Python is fun"
vowels = "aeiouAEIOU"
count = 0
for char in text:
    if char in vowels:
        count += 1
print(count)

```

**Explanation:** Check each character; increment counter if it’s a vowel.

***

### ⭐ 13. Print Numbers Divisible by 4 and 6

**Problem:** Print numbers from 1 to 50 divisible by both 4 and 6.
**Output:**

```
12 24 36 48

```

```
for i in range(1, 51):
    if i % 4 == 0 and i % 6 == 0:
        print(i, end=" ")

```

**Explanation:** Use modulo operator to check divisibility by both numbers.

***

### 🧾 14. Cumulative Sum of List

**Problem:** Print cumulative sum at each step from a list.
**Input:** `[2, 5, 3, 7]`
**Output:** `2 7 10 17`

```
numbers = [2, 5, 3, 7]
total = 0
for num in numbers:
    total += num
    print(total, end=" ")

```

**Explanation:** Add each number to a running total and print progressively.

***

### 🔄 15. Print Multiples of 3 and 5

**Problem:** Print numbers between 1–50 divisible by 3 or 5.
**Output:**

```
3 5 6 9 10 12 ... 45 48 50

```

```
for i in range(1, 51):
    if i % 3 == 0 or i % 5 == 0:
        print(i, end=" ")

```

**Explanation:** Check each number for divisibility by 3 or 5 using `%`.

***

### ⏳ 16. Reverse a String

**Problem:** Print a string in reverse.
**Input:** `"Python"`
**Output:** `nohtyP`

```
text = "Python"
reversed_text = ""
for char in text:
    reversed_text = char + reversed_text
print(reversed_text)

```

**Explanation:** Prepend each character to the result string to reverse it.

***

### 🧠 17. Find Numbers with Even Digits

**Problem:** Print numbers from 1–100 that have an even number of digits.
**Output:**

```
10 11 12 ... 99

```

```
for i in range(1, 101):
    if len(str(i)) % 2 == 0:
        print(i, end=" ")

```

**Explanation:** Convert each number to string; check if its length is even.

***

### 🔁 18. Find the Maximum Number in a List

**Problem:** Find the largest number in a list.
**Input:** `[5, 12, 3, 21, 7]`
**Output:** `21`

```
numbers = [5, 12, 3, 21, 7]
max_num = numbers[0]
for num in numbers:
    if num > max_num:
        max_num = num
print(max_num)

```

**Explanation:** Compare each element with `max_num` and update if larger.

***

### 🔢 19. Count Digits and Letters in a String

**Problem:** Count letters and digits separately in a string.
**Input:** `"Python3.8"`
**Output:**

```
Letters: 6
Digits: 2

```

```
text = "Python3.8"
letters = digits = 0
for char in text:
    if char.isalpha():
        letters += 1
    elif char.isdigit():
        digits += 1
print("Letters:", letters)
print("Digits:", digits)

```

**Explanation:** Use `isalpha()` and `isdigit()` to categorize each character.

***

### 🎮 20. Fibonacci Numbers Less Than N

**Problem:** Print all Fibonacci numbers less than a given N.
**Input:** `N = 20`
**Output:** `0 1 1 2 3 5 8 13`

```
N = 20
a, b = 0, 1
while a < N:
    print(a, end=" ")
    a, b = b, a + b

```

**Explanation:** Generate Fibonacci numbers in a `while` loop until exceeding N.

***

***

### 🧮 21. Print Odd Numbers in a List

**Problem:** Print all odd numbers from a given list.
**Example Input:**

```
numbers = [2, 7, 4, 9, 12, 15]

```

**Output:**

```
7 9 15

```

```
numbers = [2, 7, 4, 9, 12, 15]
for num in numbers:
    if num % 2 != 0:
        print(num, end=" ")

```

**Explanation:** Check if a number is **not divisible by 2** using `%`.

***

### 🔢 22. Count Uppercase and Lowercase Letters

**Problem:** Count the number of uppercase and lowercase letters in a string.
**Input:** `"Python Is Fun"`
**Output:**

```
Uppercase: 3
Lowercase: 8

```

```
text = "Python Is Fun"
upper = lower = 0
for char in text:
    if char.isupper():
        upper += 1
    elif char.islower():
        lower += 1
print("Uppercase:", upper)
print("Lowercase:", lower)

```

**Explanation:** Use `isupper()` and `islower()` for classification.

***

### ⭐ 23. Print Squares of Numbers

**Problem:** Print squares of numbers from 1 to N.
**Input:** `N = 5`
**Output:**

```
1 4 9 16 25

```

```
N = 5
for i in range(1, N + 1):
    print(i**2, end=" ")

```

**Explanation:** Multiply each number by itself using the exponent operator `**`.

***

### 🧾 24. Print Cubes of Numbers in a List

**Problem:** Print cubes of numbers from a given list.
**Input:** `[1, 2, 3, 4]`
**Output:**

```
1 8 27 64

```

```
numbers = [1, 2, 3, 4]
for num in numbers:
    print(num**3, end=" ")

```

**Explanation:** Use `num**3` to calculate the cube of each number.

***

### 🔄 25. Print Numbers Divisible by 7 but Not by 5

**Problem:** Print numbers from 1 to 100 divisible by 7 but not by 5.
**Output:**

```
7 14 21 28 ... 91 98

```

```
for i in range(1, 101):
    if i % 7 == 0 and i % 5 != 0:
        print(i, end=" ")

```

**Explanation:** Use two conditions combined with `and` and `!=`.

***

### ⏳ 26. Print Factorials of Numbers in a List

**Problem:** Print factorial of each number in a given list.
**Input:** `[3, 4, 5]`
**Output:**

```
6 24 120

```

```
numbers = [3, 4, 5]
for num in numbers:
    fact = 1
    for i in range(1, num + 1):
        fact *= i
    print(fact, end=" ")

```

**Explanation:** Use a loop to calculate the factorial of each number.

***

### 🧠 27. Count Words in a Sentence

**Problem:** Count the number of words in a given sentence.
**Input:** `"Python is fun to learn"`
**Output:** `5`

```
sentence = "Python is fun to learn"
words = 0
for char in sentence:
    if char == " ":
        words += 1
words += 1
print(words)

```

**Explanation:** Count spaces between words; add 1 to get total words.

***

### 🔁 28. Print Prime Numbers from 1 to N

**Problem:** Print all prime numbers from 1 to N.
**Input:** `N = 20`
**Output:**

```
2 3 5 7 11 13 17 19

```

```
N = 20
for num in range(2, N + 1):
    is_prime = True
    for i in range(2, num):
        if num % i == 0:
            is_prime = False
            break
    if is_prime:
        print(num, end=" ")

```

**Explanation:** A number is prime if it has no divisors other than 1 and itself.

***

### 🔢 29. Sum of Digits of Numbers in a List

**Problem:** Print sum of digits for each number in a list.
**Input:** `[12, 34, 56]`
**Output:**

```
3 7 11

```

```
numbers = [12, 34, 56]
for num in numbers:
    total = 0
    temp = num
    while temp > 0:
        total += temp % 10
        temp //= 10
    print(total, end=" ")

```

**Explanation:** Use modulo `%` to get digits and integer division `//` to remove them.

***

### 🎮 30. Check Palindrome Numbers in a List

**Problem:** Print all numbers from a list that are palindromes.
**Input:** `[121, 123, 454, 567, 787]`
**Output:**

```
121 454 787

```

```
numbers = [121, 123, 454, 567, 787]
for num in numbers:
    if str(num) == str(num)[::-1]:
        print(num, end=" ")

```

**Explanation:** Convert the number to a string and check if it reads the same forward and backward.

***

Calculate the sum of numbers from 1 to N.

N = 5
total = 0
for i in range(1, N + 1):
    total += i
print(total)


 and keep adding each number in every loop cycle.

Print each character of a string using a 

word = "Python"
for char in word:
    print(char)


Strings are iterable — the loop automatically picks each character one by one.

Print only even numbers between 1 and 20.

for i in range(2, 21, 2):
    print(i, end=" ")


Here, we step by 2 to get only even numbers.

Display all elements from a list using a loop.

fruits = ["apple", "banana", "cherry"]
for fruit in fruits:
    print(fruit)


Looping over a list gives you each element directly — no index needed.

for i in range(10, 0, -1):
    print(i, end=" ")


⏳ 7. Print Multiplication Table of a Number

Take a number and print its multiplication table up to 10.

n = 3
for i in range(1, 11):
    print(f"{n} x {i} = {n * i}")


Find factorial of a number (e.g., 5! = 1×2×3×4×5).

n = 5
fact = 1
for i in range(1, n + 1):
    fact *= i
print(fact)


Multiply all numbers from 1 to n sequentially to find the factorial.

🔁 9. Print Digits of a Number (Using while loop)

Display each digit of a number separately.

num = 1234
while num > 0:
    digit = num % 10
    print(digit)
    num //= 10


 to extract the last digit and integer division 

1
2
Fizz
4
Buzz
Fizz
7
8
Fizz
Buzz
11
Fizz
13
14
FizzBuzz
...


for i in range(1, 21):
    if i % 3 == 0 and i % 5 == 0:
        print("FizzBuzz")
    elif i % 3 == 0:
        print("Fizz")
    elif i % 5 == 0:
        print("Buzz")
    else:
        print(i)


If both 3 and 5 divide the number, print 

 first — otherwise the correct single case.

 Calculate the sum of all even numbers in a given list.

numbers = [1, 4, 7, 10, 12]
total = 0
for num in numbers:
    if num % 2 == 0:
        total += num
print(total)


 Loop over each number; if divisible by 2, add to 