let 100a+10b+c = m and (100b+10c+a)=n
m-n = (100a+10b+c) - (100b+10c+a) = 99a-90b-9c
its obvious that every such (m-n) will be divisible by 9. my question is : is there any theorem i could use to make this proof more presentable?
2026-04-08 04:17:37.1775621857
a natural number m is obtained by rearranging the digits of another natural number n. Show that m − n must be divisible by 9.
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