Description: Topic B focuses on spatial relationships and structuring as students organize equal groups (from Topic A) into rectangular arrays. In Lesson 5, students compose arrays either one row or one column at a time and count to find the total using the scattered sets from Topic A. In Lesson 6, students decompose one array by both rows and columns. Thus, an array of 4 rows of 3 teddy bears can be pulled apart to show either 4 rows of 3 or 3 columns of 4. Also, students see that when another row or column is added or removed, so is another group, or unit. In Lesson 7, students move to the pictorial as they use math drawings to represent arrays and relate the drawings to repeated addition. In Lesson 8, students work with square tiles to create arrays with gaps, composing the arrays from parts to whole, either one row or one column at a time.*Teacher Advisor is 100% free.