These are Alternate Arithmetic Methods to the ones usually taught in schools.
Lattice Multiplication 2 more examples (eliminates carrying): http://www.youtube.com/watch?v=NOvWelg2SLM
Scratch Addition: Quick and easy way to add a column of single digit numbers using the Scratch or Dot Method. http://youtu.be/aobn006_rl0
Multiply by 9 the easy way: multiply single digits by 9, and larger numbers when all the digits are the same, like 88888 x 9http://www.youtube.com/watch?v=VFHDn4TKHDM