Which is the best estimate for the sum of 2/9+10/11 ? You can use the number line to tell if each fraction is closer to 0,1/2, or 1. Then add those estimates together. • A.0+0=0 • B.1/2+1/2=1 • C.1+1=2 • D.0+1=1

its 4 because 2 times 2 is 4, if you double the number two you get four

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