I have been teaching for 24 years.  I taught seventh grade math my first two years in Hagerstown, Md.  The first year we did 90 minute classes every day and the second year we did 60 minute classes every day.  I have taught in Pennsylvania the past 22 years.  The first 20 were at the middle school level where I had seventh and eighth grade, both Pre-Algebra and Algebra.  The past two years I have been at the high school where I teach Geometry, Algebra 2, and Consumer Math.  We have 40 minute periods every day.