forgot my passcode on my i4

[iMore Question]

my daughter got a new phone and gave me her old iphone4 that she hasnt used in months and months and of course has forgotten her passcode

 

[Tartarus]

It's her birth year or her PIN number for her debit card.

On a serious note: since it's your daughters iphone, it's best to connect it to iTunes, enable DFU MODE and restore the phone as new.

http://m.imore.com/how-to-iphone-ipad-dfu-mode