This is quite a nice mathematical trick, but nothing more. It may allow children to be able to perform large multiplication at a young age, but it is also setting them up to be confused later on by providing them with a method which abstracts from the actual arithmetic. What on earth is going to happen when they run into algebraic multiplication? I think it is much more useful to teach them to split up the parts of the numbers and multiply those, if they are too difficult to be multiplied mentally. For example instead of 11x22 do 10x22 + 20 + 2.