Here are the small ones. (You may not be able to tell from the pictures but each section has a staple separating it from its neighbors; that way, the digit cards have a snug little place to fit in.)
My charts go up to the millions since I teach 4th grade.
This type includes decimals...
...though I fold it to cover up the sections we do not go over.
I keep spare digit cards in a baggie in the tubs that I store the charts in. As you can see in the picture, each card has a digit 1-9 and a zero written on the opposite end.
This is where I keep them!