A forum with speakers both in support and in opposition to the adoption of the Common Core education standards will be held at 7 p.m. Tuesday at Mansfield High School. Speakers will be Sandra Stotsky, a former member of the Common Core Validation Committee, who did not sign off on the standards as adopted; Linda Noonan of the Massachusetts Business Alliance for Education, which recommended adoption of the standards in 2010 and continues to support them; Jamie Gass of Pioneer Institute’s Center for School Reform, which has been outspoken in its challenges to the standards; and Mary Anne Alliegro, a member of Liberty Chalkboard, also opposed to Common Core. Selectman Olivier Kozlowski said he organized the forum in his role as a parent of two children in the school system. He said the nationwide standards for mathematics and English will have financial impacts on local school districts. “We managed to get speakers to represent all sides,” Kozlowski said.