Ask students to explain the pattern they see. Ask students what is the same and different about each representation. Reinforce the idea that the array placement of the counters makes counting and figuring out the number easier. Introduce students to a new pattern arrangement. Ask students to make the triangle dot numbers to complete the chart.
Students can use the centers to assess the triangle group before it is recorded on the chart.
After the students have completed the chart, discuss the triangle pattern they discovered. Test the rectangular shape with counters to find out. Discuss how the shape of the counters in the squares, triangles, and rectangles help in determining the number. Use counters to continue the pattern two more times. Fill in the numbers.