I was recently questioned by Hannah Suppiah about writing code to calculate fibonacci numbers and it brought my uni days flooding back. As an illustrative tool and a quick bit of nostalgia, I wrote this simple JQuery example of the fibonacci tree.

There 2 lines of JQuery needed to work out the n’th fibonacci number.

```
{.js name="code"}
function fib(n){
if(n<=1){//if we are trying to get the first number then return it
return 1;
}
//otherwise return the sum of the last 2
return fib(n-1)+fib(n-2);
}
```

Because a fibonacci number is defined as the sum of the previous 2, as simple bit of recursion is required to calculate it (re-cursing down until we get to a known value [i.e 1]).