Question: What doesn't this work:

```
(int)08 == (int)09==0

```

But this and this does?

```
(int)07==7 
(int)06==6 

```

Answer: 
because `08` and `09` are not valid octal numbers. [see warning in docs](http://docs.php.net/types.integer).
```
// Syntax error
//(int)08 == (int)09==0

// This works
(int)08==0;
(int)09==0;

// This also works
(int)08 == ((int)09==0);

```