Subtraction Strategy “CONSTANT DIFFERENCE”

Subtraction Using Constant Difference – 3rd from Trinity Episcopal School on Vimeo.

 

Constant-difference strategy:
An effective strategy for solving subtraction problems mentally is based on the idea of a constant difference. Constant difference refers to the idea that the difference between two numbers does not change after
adding or subtracting the same quantity to both numbers.
Here is a game that allows students to use constant difference for mentally subtracting numbers:

 https://play.dreambox.com/student/dbl/TeacherTool_ConstantDifference?atype=2&back=http%3A%2F%2Fwww.dreambox.com%2Fteachertools&eng=Intermediate