Two county teachers selected to be state finalists for awardBy GLENN McMAHAN News* Post StaffFrom out of the chalk-dusted grist mill of public education, two teachers in Frederick County have emerged as state finalists for math teaching and could win presidential recog* nition.As Maryland’s elementary and secondary level finalists for the 1992 Presidential Awards for Excellence in Mathematics Teaching, Joyce Bruebey and Kathleen House have been selected by the National Science Foundation as “model teachers.”If they win the nationwide award in their categories this fall, they will spend time at the White House and spend cash for their schools.The National Science Foundation will send three state winners to the White House for presidential recognition and a check for $7,500 to spend on behalf of their school.JOYCE BRUCHEY KATHLEEN ROUSE