Cargo Captain (Multi-digit Subtraction)

In math, many students learn procedures without understanding what they are doing. For example, when students “borrow” or regroup during subtraction, they can cross out numbers and get the correct answer, but can they explain why this procedure works?

The Cargo Captain (Multi-Digit Subtraction) Gizmo is a fun way for students to gain an understanding of this process. In the Gizmo, students control a spaceship that transports cargo stored in barrels, crates, and holds to various fictitious planets. There are 10 barrels in a crate and 10 crates in a hold. When the ship goes to a new planet, students unload a certain number of barrels. To do this, they will often have to “unseal” a hold or crate so they can unload the exact number of barrels. As students break down holds into crates (hundreds to tens) or crates into barrels (tens to ones), they will gain a natural understanding of regrouping and learn about how the process is useful when subtracting numbers.