“Secret Number Codes” is an excerpt from 312 Things To Do with a Math Journal, available as a special pre-publication ebook edition at my publisher’s store or for preorder through many online retailers. Read more about my playful math books here.
The Math Game Monday posts will be available for one week only. If you missed this one, explore the links in the sidebar. There are more than forty free games scattered around the blog. Have fun playing math with your kids!