Title: Introducing addition and subtraction symbols to first graders
Description: <a href="http://uf.catalog.fcla.edu/uf.jsp?st=UF000940984&ix=pm&I=0&V=D&pm=1" rel="nofollow">http://uf.catalog.fcla.edu/uf.jsp?st=UF000940984&ix=pm&I=0&V=D&pm=1</a>
Subjects: Mathematical notation--Study and teaching, Arithmetic--Study and teaching.