**Check out this sequence:**

**Can you figure out what the next term will be? Maybe you saw the pattern right away... and maybe you didn't**

**Each term is found by adding the two previous terms:**

**So, what's the next term?**

**What's the 50th term?**

**Hmm... Not as easy as it was with those squared guys...**

**Unfortunately, with this guy, you'd have to find all the terms leading up to the 50th term -- since he's based on the two before them and so on. When this happens, it's called recursion.**

**By the way, this last sequence is very famous! It's called the Fibonacci Numbers. (Named after Fibonacci, of course.)**

**How about this sequence?**

**Can you guess the next term?**

**What about the 20th term?**