Volume Warm-Up

Begin by presenting the slideshow to the class.

• As you move past the title slide, students are asked to solve a multiplication sentence with three factors.  After students have given an answer, ask for students to explain how they solved it.  Record these explanations on the board.  For example, some students might multiply the first two factors first, while others start by multiplying the first and third factors together. This problem prompts students to remember the associative property of multiplication and how to multiply with more than two factors.
• On the next slide, students are presented with multiple arrays.  Rather than asking how many cupcakes, ask students "What do you see?"  Record student answers as mathematical equations.  For example, if a student says 'I see four groups of six cupcakes', record the equation 4 x 6 = 24.  Tell students that you see two rows of three cupcakes four times, pointing out or circling each factor in the image.  Record the equation 2x3x4.
• Repeat the same procedure on the next slide.  If no students share an equation using three factors, ask students to think about how you can see the donuts in rows and columns -- help students reach the equation 3x4x3 or 4x3x3.
• On the last slide, ask students how this image is different than the other two.  Point out that the arrays are now stacked on top of each other.  Students should identify the equation 2x3x4 (or a rearrangement of those factors).
• Point out to students that when the arrays are stacked in a solid shape, some of the objects are hidden.  In this image, only 18 rolls of toilet paper are visible, but we know there are 24 total rolls by imagining the stack as two arrays of 12.  (Some students may also see four arrays of six or three arrays of eight standing one in front of the other; those perspectives work with the equation also.)