🔹 Basic Level (1–7)

1. Create a function that prints "Hello World".
2. Create a function that takes a name as input and prints:
   👉 "Hello, <name>"
3. Write a function to add two numbers and return the result.
4. Create a function to check if a number is even or odd.
5. Write a function that returns the square of a number.
6. Create a function that converts Celsius to Fahrenheit.
7. Write a function that finds the maximum of two numbers.

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🔹 Intermediate Level (8–14)

8. Create a function to calculate the area of a circle.
9. Write a function that counts the number of vowels in a string.
10. Create a function that reverses a string.
11. Write a function that checks if a number is prime.
12. Create a function that takes an array and returns the sum of all elements.
13. Write a function that finds the largest number in an array.
14. Create a function that calculates factorial of a number.

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🔹 Advanced Level (15–20)

15. Convert a normal function into an arrow function.
16. Write a function with default parameters (e.g., greet user with default name).
17. Create a function expression that multiplies two numbers.
18. Write a callback function example:
    👉 One function should accept another function as argument.
19. Create a function that filters even numbers from an array.
20. Build a mini calculator using functions:
    👉 add, subtract, multiply, divide

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🚀 for students

👉 Combine everything:

• Take user input
• Use functions
• Display result in HTML

Mini project using functions (calculator app)