iPad 2 passcode keypad not working

I have a iPad 2 and haven't used it in a while. Powered it up and tried the passcode but the 1, 2, 4, 5, 7, 8, & 0 numbers won't work. Only 3, 6, & 9 responds. I have reset the iPad a number of times with various techniques (i.e. hold the home key and power button down at the same time til restart, or press the power button, slide to power off, when powered down hold the home key and power button down at the same time til the apple logo appears, goes away, and appears again then release and allow system to start). Any ideas on how to resolve this issue? Thanks in advance.