These Math Adding Strips are the perfect way to help children learn their basic addition facts. The strips are designed for children to use Lego to model each math fact, ensuring the children understand the concepts rather than simply memorize meaningless facts. These strips also work really well with blocks, pegs, or many other manipulatives. The set includes 20 pre-made cards and 20 cards you can personalize with any addition facts you want to help students learn.