type handling error in PowershellLab demo

Stumbled across this on Twitter. In playing around with it, there's some incorrect behavior around types.

Example: 

```Powershell
> $mynum = 5
> $mynum * 10
5
5
5
5
5
5
5
5
5
5
```

if a type is specified, it works as expected:

```Powershell
> [int]$mynum = 5
> $mynum * 10
50
```