The Fibonacci Sequence is the series of numbers:
0, 1, 1, 2, 3, 5, 8, 13, 21, 34, ...
The next number is found by adding up the two numbers before it.
The 2 is found by adding the two numbers before it (1+1)
Similarly, the 3 is found by adding the two numbers before it (1+2),
And the 5 is (2+3),
and so on!
Example: the next number in the sequence above is 21+34 = 55
It is that simple!
Here is a longer list:
0, 1, 1, 2, 3, 5,...