Fibonacci Series or Fibonacci Sequence

# Fibonacci Series or Fibonacci Sequence

## What is the Fibonacci sequence?

The Fibonacci series or Fibonacci sequence is one of the most famous formulas in mathematics.
Each number in the sequence is the sum of the two numbers that precede it. So, the sequence goes: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, and so on. The mathematical equation describing it is:

Xn + 2 = Xn + 1 + Xn

For example, 34 = 21 + 13, 21 = 13 + 8, etc.
A mainstay of high-school and undergraduate classes, it's been called "nature's secret code," and "nature's universal rule." It is said to govern the dimensions of everything from the Great Pyramid at Giza, to the iconic seashell that likely graced the cover of your school math textbook.

The Fibonacci series is a very useful tool in mathematical series.
The Fibonacci sequence up to 15 terms are as follows:

0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 56, 90, 146, 236, 382......

Question 1: Write the 20th term of a Fibonacci series.

Question 2: Can you write the 100th term of a Fibonacci series?