Is a quicker way available to find the volume of a rectangular prism than counting the number of cubes needed to fill it one by one? Why can we multiply to find the volume of a rectangular prism? These questions are a focus in the revised math TEKS for grade 5.
Given rectangular prisms whose length, width, and height are whole numbers of units, we can view the prism as made of a three-dimensional array of unit cubes. By viewing these arrays as consisting of layers (either horizontal or vertical) and noticing that the layers themselves can also be decomposed into equal groups, students should come to realize that they can use multiplication rather than counting one by one to determine the total number of unit cubes required to fill a rectangular prism in an efficient way.
The following series of videos model the volume activity presented in the 5th grade Grade Level Team Meeting held on Jan 13, 2015. The activity modeled in the videos can be found in the 5th grade Grade Level Team Meeting Moodle.
Given rectangular prisms whose length, width, and height are whole numbers of units, we can view the prism as made of a three-dimensional array of unit cubes. By viewing these arrays as consisting of layers (either horizontal or vertical) and noticing that the layers themselves can also be decomposed into equal groups, students should come to realize that they can use multiplication rather than counting one by one to determine the total number of unit cubes required to fill a rectangular prism in an efficient way.
The following series of videos model the volume activity presented in the 5th grade Grade Level Team Meeting held on Jan 13, 2015. The activity modeled in the videos can be found in the 5th grade Grade Level Team Meeting Moodle.