I used Base 10 block sponges, in my Travels in Math - math center. This is a quick and easy center to set up. The packet comes with 10 assignments which I recommend stapling into a book. The math books can be kept in the math center. Put a number label at the top of the front cover of the math books and train your students to keep the books in number order. There is an assignment sign that you hang by the center to remind your students which page they need to complete in their book. Here is a copy of the number labels:
I used BD cartoon shout font to make these labels. That is a free font that you can download from several different sites on the internet.
Here's a sneak peek of the Travels in Math - math center:
The packet comes with 10 assignment pages.
There are addition and subtraction problems with regrouping.
There is a math mat to use with Base 10 blocks.
Assignment sign to remind students which page they need to complete.
Cut these picture apart and hang them on the assignment sign.
This packet is available at my TPT store for $3.