As they work toward understanding these concepts, they focus on developing mathematical models for concrete problem situations. The number sentences that they write to describe these problem situations form a foundation for more sophisticated mathematical models. The cumulative progress indicators for grades K-2 appear below in boldface type. Each indicator is followed by activities which illustrate how it can be addressed in the classroom in kindergarten and in grades 1 and 2. Understand and represent numerical situations using variables, expressions, and number sentences.
Students represent a problem situation with an open sentence.
Students read The Doorbell Rang by Pat Hutchins. They act out the story and realize that many different combinations of students can share 12 cookies equally. Students make a table relating the number of people and the number of eyes. They use a symbol such as a stick figure to represent the number of people and a cartoon drawing of an eye to represent the number of eyes and then express the relationship between them. Represent situations and number patterns with concrete materials, tables, graphs, verbal rules, and number sentences, and translate from one to another.