As set out by the National Governors Association (NGA) and the Council of Chief State School Officers (CCSSO) in the Common Core State Standards Initiative. For more information, please visit the Number and Operations: Base Ten domain at the Common Core State Standards website.
July 22, 2013
Liping Ma describes some differences between American and Chinese math educators, specifically concerning the idea of regrouping. "It's always easier for children to subtract three from ten than from thirteen."
A child works to discover "how many more" a person has.
Joanne Mulligan provides an example of a six-year-old's personal rules for counting to 20.