Double-Digit Addition Math Mats provide a way for your students to practice double-digit addition in four different ways: base ten manipulatives, standard algorithm, expanded form, and a number line. There is a version of each math mat that has an example, a version that is editable, and a version with a fixed background so that students can use it digitally (simply have them add text boxes). These math mats are perfect for laminating and using with dry erase markers or manipulatives in a math center. There is also a file that contains all four methods on one slide, so that the same problem can easily be shown in four different ways.