This is a material I use to ease the transition from horizontal to vertical addition and to show the commutative property of addition i.e., when two numbers are added, the sum is the same regardless of the order of the addends. Those were quite fancily technical terms, but this work is fairly simple and easily enjoyable (even I enjoy making these!). For some reason, black has magic and the children like using the white chalk/pencil/dermatograph over the black paper. Just make sure your paper is not jet black--choose a lighter shade of black--so that your black ink can be printed on the black paper.
You may download the template here.