



 
Hi Nazrul, I need to write a proof and am not sure where to start, I like to write out the properties I know for the given situation. In this case, the properties of natural numbers: Closure under addition: If a and b are natural numbers then the sum of a+b is a natural number Looking at what you need to prove, I try to recognize any familiar patterns; I know you will have to use the properties commutativity under multiplication and distributivity. Hope this helps, Janice  


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