This document summarizes a presentation about preparing elementary school teachers to understand elementary mathematics. It discusses how elementary mathematics concepts can be complex and how focusing on children's mathematical thinking can help prospective teachers (PSTs) engage more deeply with mathematics. The presentation addresses four principles: 1) How students typically learn mathematics is problematic, 2) Learning concepts is more powerful than procedures, 3) Students' reasoning is varied and complex, and 4) Elementary math is not as elementary as assumed. Research found PSTs who learned about children's thinking improved their math knowledge and developed more sophisticated beliefs than those who did not.