Description: One of a series of documents describing the progression of a topic across several grade levels, informed both by research on children's development and by the structure of mathematics. Students represent these problems with concrete objects and drawings, and they find the answers by counting (Level 1 method). For Put Together/Take Apart with Total Unknown, they make or draw the two addend sets, and then they count the total number of objects to give the answer. But as a general method they learn how to find answers to these problems by counting on (a Level 2 method), and they understand and use this method.*Teacher Advisor is 100% free.