Mathematical construction, informal number work for busy hands grades one and two This book, "Mathematical construction, informal number work for busy hands grades one and two", by Nora Louise Laffin, is a replication of a book originally published before 1911. It has been restored by human beings, page by page, so that you may enjoy it in a form as close to the original as possible. This book was created using print-on-demand technology. Thank you for supporting classic literature.