The meaning of the decimal representation of a number 0.d1d2d3 . . (where the digit i is one of the numbers 0, 1, 2, . ., 9) is that 0.d1d2d3d4 . . = d1/10 + d2/10^2 + d3/10^3 + d4/10^4 + . . show that this series always converges.

the correct answer is you spend $55.78 more in a brand store that buy ing in a normal store.

step-by-step explanation:

brand = spend   $ 135.85 total

store = spend $80.07 total

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