Ned took a test with 25 questions. He lost 4 points for each of the 8 questions he got wrong and earned an additional 12 points for answering a bonus question correctly. How many points did Ned receive or lose overall?

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