The history of math is murky, predating any written records. When did humans first grasp the basic concept of a number? What about size and magnitude, or form and shape? In my math history courses and ...

Help D.C. with number sentences and ten frames, then learn about groups of up to 20. Join Mrs. Gray for a Mystery Math Mistake with D.C. He needs help figuring out his number sentences to match ten ...

While each product featured is independently selected by our editors, we may include paid promotion. If you buy something through our links, we may earn commission. Read more about our Product Review ...