Khan Academy
Khan Academy: Arithmetic and Pre Algebra: Associative Law of Addition
This video explains the associative law of addition by writing an expression in a different way. Practice problems are available. [2:10]
Khan Academy
Khan Academy: Arithmetic Properties: Associative Law of Addition
This video explains the associative law of addition by writing an expression in a different ways.
Khan Academy
Khan Academy: Arithmetic Properties: Commutative Property for Addition
This video shows how to write an equivalent numerical expression using the associative and commutative properties of addition. [3:22]