A detailed characterization of math teaching patterns using the videos that teachers recorded themselves as part of the 2005 chilean national teacher assessment program is presented. This is a new compulsory teacher assessment program, but in 2005 teachers volunteered to initiate the program. It includes the analysis of more than 700 videos of 40 minutes each, both from elementary and high school classes, from different regions of the country, containing classes of algebra, geometry, data and numbers strands. One slice of 4 minutes of each video were studied. Each slice were randomly selected from different moments of the class: first 4 minutes, from minute 10 to 14, from minute 20 to 24, from minute 30 to 34 and the last 4 minutes. More than one hundred vriables were codified by independent coders. The codification methodology was successful and stable across different coders, making possible to analyse huge amount of data. The main findings were: very little automomous student participation (only one mathematical question made by students per 40 minutes class), no proofs are made by teachers, no use of information technology, almost no use of textbooks, almost no explicit use of metaphors.