He almost exclusively used sample problems provided by the researchers for both of his classes, but formatted them in a different way for the control class. When introducing the conceptual approach for a new topic, he was observed to write the strategy on the board word for word from the researchers' examples and refer to the example on paper as he did so. Students in the CPS section were given blank worksheets that prompted them for each step in the strategy and to format their solutions as two columns, and they often worked in cooperative groups. Students' homework was graded and at least one problem on each exam (for the CPS class) required them to complete a strategy and two-column solution. Teacher B described his classroom implementation of CPS in the following way