Digi-Blocks are manipulatives which are an alternative to traditional base 10 blocks. They are used in the same way to model place value, but Digi-Blocks are based on a nested design, meaning that all of the blocks pack into each other and the “smart box” only closes when there are 10 blocks inside. While these are valuable at all grade levels for place value concepts and modeling all four operations, in my opinion they are most useful for modeling decimals and division. In fact, their website features a video where a 4 year old demonstrates long division using the blocks. (see also the embedded video below about using the blocks to model decimal division.)
In addition to the website Digi-Blocks has a Facebook page where you can see many videos demonstrating how to use these manipulatives to teach different math concepts, print activity sheets and games to use with the blocks, and more.The page also periodically posts promo codes for online orders of their products. (Besides the blocks themselves they sell teacher guides, place value mats, number lines, and counters.)
At Louise and Kool you can find an entire resource list of PDF lessons and video demonstrations using Digi-Blocks. They also sell the blocks.
Here are some other lessons and video ideas for using Digi-Blocks across grade levels.
Digi-Blocks Castles a TPT freebie for kindergarten/first grade
Unpacking Tens- a 1st grade lesson from C Palms
Introducing Decimals with Digiblocks
Please see my Manipulatives page for more recommended math manipulatives.