The T-Shirt Factory: Place Value, Addition, and Subtraction is one of eight units in the Contexts for Learning Mathematics’ Investigating Number Sense, Addition, and Subtraction (K–3)
This unit begins with the story of Grandma Eudora’s T-Shirt Factory. Grandma Eudora is part of the Masloppy family—a large, endearing family that finds it difficult to keep track of things. Everyone is forever losing, misplacing, and looking for things. One of the children, Nicholas, decides to sort, organize, and take inventory of things in the house, including Uncle Lloyd’s T-shirts, which he arranges in rolls with rubber bands. One day as Uncle Lloyd is doing the laundry, Itchy, the family dog, knocks over a bottle of bleach. The result of this mishap is colorful tie-dyed T-shirts, which Grandma begins to sell in a highly successful business—Grandma Eudora’s T-Shirt Factory.
The idea of the T-shirt factory is brought to the classroom as a simulation. Children work in groups (companies with factories) making and selling T-shirts and organizing their warehouses. The main focus of the unit is place value, regrouping, equivalence, and the recording of the inventory. Students keep track of inventory before and after shipping orders, as boxes and rolls in the warehouse are opened so that orders can be filled. Within the context of the need for pencil-and-paper recordings of transactions, the standard addition and subtraction algorithms are explored. The concept of place value is developed to three and four places during the simulation as children organize the warehouse: packing rolls of T-shirts (ten to a roll) in storage boxes that hold ten rolls and calculating the income from sales of T-shirts at $10 each. Students, playing the role of employees, keep accounting ledgers to record the sales of specific sizes and the total company inventory.
