Number line – distance and absolute value

MathematicsNumbers & ArithmeticAges 12–13

Two screens: Situations places two points in three familiar contexts (two houses on a street, temperatures during a day, height above sea level) so you can read the signed difference b − a and the distance |a − b|; Number line lets you drag or type the two points a and b (including decimals and negative numbers) on an abstract horizontal or vertical line and compare b − a with |a − b| = |b − a|. Adapted from the "Number Line: Distance" simulation by PhET Interactive Simulations, University of Colorado Boulder (CC BY 4.0); rewritten.

Lesson: Absolute value of real numbers