These always fall apart after a little bit of continuous use. The pages are still good to use. Separate, punch holes and put them in a 3-ring binder. Then take out the specific one your child needs to use. More than one child can work from the same book this way too. They are easier to write and clean too.
You can also make your own write and wipe with a grease pencil and contact paper. Put the contact paper over any worksheet you need to use often or with more than one child.
