Posted by Tee on .
What are the groupable models and the pregrouped/Trading models of baseten concept?
How are they different?
I have been searching for a definition for these terms but my efforts deem unsuccessful. Could u asset me plzz.

Baseten concept 
bobpursley,
In base 10, blocks of one can be combined to make blocks of length ten, then the strings of ten can be grouped to make a block of 100. The individual blocks are groupable, but a block of lenght ten is called pregrouped, and can be traded for ten individual blocks.
These blocks, or some in rod form, were popular in the sixties, and seventies, as manipulatives for number sense, but research has been clear that that they fail to help children understand number structure and number operations, albeit they understood the trading game well.
Groupable: can be combined to make units of 10 or 100
Pregrouped: blocks or rods precombined in length 10
Trading model: A block of length 10 which can be traded for ten individual blocks.