Partial products - multiplying in parts

Partial products means we multiply numbers part-by-part. For example, 5 x 36 is done as 5 x 30 and 5 x 6, and those two parts are added. You can quite easily do these in your head when one number has two digits and the other has one. This concept is very important, as it is the basis for the regular multi-digit multiplication algorithm studied in 4th grade. I also teach it in my book Math Mammoth Multiplication 2 at - available both as an inexpensive download ($5.10) and as a printed copy.