Beckmann, Sybilla.
Mathematics for Elementary Teachers
. USA: Addison-Wesley, 2003.
Carpenter, Thomas et al.
Thinking Mathematically
. Portsmouth, NH: Heinemann, 2003.
Foresman, Scott.
Scott Foresman-Addison Wesley Mathematics
. NY, NY: Scott Foresman, 2002.
Hong,Kho Tek, et al.
Primary Mathematics 6A
. Singapore: Times Media Private Limited, 2003.
Hong, Kho Tek, et al.
Primary Mathematics 6B
Singapore: Times Media Private Limited, 2003.
Lampert, Magdalene.
Teaching Problems and the Problems of Teaching
. New Haven, CT: Yale University Press, 2001
Loyd, Sam.
Mathematical Puzzles
. New York: Dover Publications, 1959.