You can see one of the beginning stages of how Racks & Tubes is used in Ms. Brenna's class video. With this material, it is clear that the students are researching division and not simply finding the quotient, but also finding the position occupied by the result of their work. At this stage, they are recording the steps of their concrete work in order to lead to abstract thought.
• Seven test tube racks: 3 white (simple family that contains green, blue, red beads representing units, tens, hundreds); 3 gray (thousands family also with green for unit, blue for tens, and red for hundreds); and 1 black (millions family with just green for units)
• Seven bowls that correspond to the colors above for placement of the dividend (external colors are for place value family, internal colors are for each place value within that family
• 10 tubes in each rack, each containing 10 beads in the appropriate color for exchanging
• Frames in green, blue, and red for the skittles used for the divisor, as well as 81 holes for placement of the dividend and for discovering the quotient
• Boxes containing "skittles" - 9 green, 9 blue, 9 red (for divisor)
They have also previously completed "Decurion Division" where one student wore a blue ribbon to represent a person in charge of ten people. They saw that when they were this "blue skittle" they had to distribute whatever they received to 10 people.
Cinematography and Editing: Tyler Hach
Sound: Ian Farmer
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