2-digit addition crossing 100 with regrouping using base-10 blocks.
A worksheet featuring 2-digit addition problems with regrouping, illustrated with base-10 blocks (green rods and yellow cubes) to visually represent numbers. Problems include 66 + 37, 65 + 43, 57 + 43, 37 + 78, 26 + 94, 55 + 55, and 87 + 15.