Exit a five-sided solid has the numbers 1, 2, 3, 4, and 5. what is the probability of rolling two five-sided number solids and getting a sum of either a 3 or an 8?

not only in mathematics, scientific proof also are required in the other field of science. also maths proofs are of particular structure, containing steps and logics. so proving is like doing science, it is science. that's why it is important to prove. 

an inaccurate proof leads to errors, or stating results that are not accurate.  which wil mess the probelm up you dont want this