Learn Intermediate Python 3 with this interactive course, and get a handle on the most popular programming language in the world.

Join us on an interactive journey through the syntax and functionality of Python. The course begins by exploring the basic building blocks before moving on to higher-level concepts such as functions and loops. Fun quizzes and coding challenges will accompany you along the way to help enforce all the concepts covered in the course.

By the time you're done, you'll have the skills you need to create your own basic applications in Python 3.

Learn Intermediate Python 3

## Problem Statement
Fibonacci sequence is a series of numbers where every number is the sum of the two numbers before it. The first two numbers are `0` and `1`:

```
0 1 1 2 3 5 8 13
```
You must write the `fib()` function which takes in a positive integer, `n`, and returns the *n-th* Fibonacci number. However, instead of using recursion, your function must use any of the loops.

### Sample Input
```python
n = 7
```

### Sample Output
```python
8
```

## Coding Challenge
Take some time to figure out how the recursive approach can be translated into an iterative one. Consider all edge cases that could occur. 

If `n` is negative or zero, return `-1`.

If you feel stuck, feel free to refer to the solution review in the next lesson.

Good luck!




# Problem Statement
Fibonacci sequence is a series of numbers where every number is the sum of the two numbers before it. The first two numbers are `0` and `1`:

```
0 1 1 2 3 5 8 13
```
You must write the `fib()` function which takes in a positive integer, `n`, and returns the *n-th* Fibonacci number. However, instead of using recursion, your function must use any of the loops.

## Sample Input
```python
n = 7
```

## Sample Output
```python
8
```

# Coding Challenge
Take some time to figure out how the recursive approach can be translated into an iterative one. Consider all edge cases that could occur. 

If `n` is negative or zero, return `-1`.

If you feel stuck, feel free to refer to the solution review in the next lesson.

Good luck!




Let's implement the Fibonacci series using loops!

Introduction

Data Types and Variables

Conditional Statements

Functions

Loops

Python Exam I

Data Structures

Libraries

Appendix

Python Exam II

Exercise: Fibonacci Series

Problem Statement

Sample Input

Sample Output

Coding Challenge