a provisional cast on is ANY cast on that is undone (so that live stitches can be picked up..
but be aware:
stitches are like V's (you knit into top (open end of V))
-/ -/ -/ -/ -/ (5 stitches (-=knit into space)
when you undo a provisional cast on, you turn the work upside down, and -- in doing so, the V's become A's
/-\ /-\ /-\ /-\ /-(5 upside down stitches--)
Only now, you knit into non - area (or red dashes, below)
/ [COLOR=Red]-[/COLOR]/ [COLOR=Red]-[/COLOR]/ [COLOR=Red]-[/COLOR]/ [COLOR=Red]-[/COLOR]/ \ NOTE: there are only 4 red dashes..
because you "lose" a half stitch (bold) at beginning and end of row.
so 5 regular stitches becomes 5-1 (4) picked up stitches)
you can fudge a bit, and get 5 (and if you work in round, there is no loss) but when knitting flat, you'll alway have 1 fewer provisional stitch than cast on.