A discussion is presented concerning variables associated with children's representation of certain addition and subtraction problems. Problem components are classified as physical, pictorial, sensual, verbal-spoken, verbal-written, symbolic, or internal. Problems are discussed as abstract (symbolic) or nonsymbolic. Three problem components are…

The measurement of change in quasi-experimental educational research was discussed. Problems related to measuring change exist to varying degrees in all research designs; these issues are less troublesome in experimental studies because the investigator can manipulate the interest variables and observe their effects on other variables. Measuring…