This innovative teaching methodology allows students to learn and generalize the concepts of addition and subtraction. The basic tool used is the number line, a definitional mathematical concept: all math depends on an understanding of the order of and relationship between numbers. Using the number line not only allows the student to master the listed skill but also gives the student the foundation needed to master the math skills that follow in the curriculum. The Number line/hundred chart is an example of a “concept prompt.” NLG uses “concept prompts” whenever practical in teaching skills that have stimuli or responses that are similar or “overlapping”. Initially developed to assist students who had failed using other teaching methodologies, this method is now the standard at NLG and has been successful with a variety of learners. The write up includes 5 photos of learning materials.