User blog comment:Googleaarex/Multiplication numbers/@comment-5029411-20130317150252

10^n = X(X)(X)(X)...(X)(X)(X) (n-1 (X)'s)

10^10 = X(X)(X)(X)...(X)(X)(X) (X-1 (X)'s)

10^10^n = X(X)(X)(X)...(X)(X)(X) (X(X)(X)(X)...(X)(X)(X) (n-1 (X)'s)-1 (X)'s)