Letters on Playing to Learn

http://www.nytimes.com/2010/02/08/opinion/l08teach.html?ref=opinion

Two of the letter writers would like to see elementary Math education to go beyond the four operations.
"In addition, in any mathematics curriculum, including early childhood, children are capable of learning much more than the four basic operations. Where are geometry and early algebra? What about logic, measurement and estimation?"

The same letter writer as quoted above also points out the lack of social studies in Engel's ideal early schooling.