How do you spell forty pounds?

Forty pounds can be spelled in a few different ways depending on the context:

For weight:

* 40 lbs (abbreviated)

* 40 pounds (written out)

For currency:

* £40 (British pounds)

* $40 (US dollars, if that's what you meant)

Let me know if you have a specific context in mind, and I can give you a more precise answer.