Number Ninjas: Level 4, Add and Subtract, is the fourth part of an entire unit on Numbers and Operations. Throughout each of the 5 levels of the Number Ninjas unit, students level up to different colored ninja belts! This level focuses on Addition and Subtraction! Part 1: AdditionMental Math addition strategiesAddition with Base Ten BlocksAddition using the Standard AlgorithmPart 2: SubtractionMental Math subtraction strategiesSubtraction with Base Ten BlocksSubtraction using the Standard Algor