iPad passcode,iTunes

I get home from work after a busy day in the office and try to use my iPad to catch on some Android books had saved for offline reading there.
I can't use the devii as it's off and so power it up and coming back later to use my buggy mind can't recall the passcode.
To make it worse hadn't synched it with iTunes on my machine and am fucked.
I try some few passcodes with no avail and call the shorts a full reset though all have to lose all data damn Tim Cook and company.