Question 1078876
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N = 100a+10b+c
K = 100c+10b+c

N-K = (100a+10b+c)-(100c+10b+a) = 100a+10b+c-100c-10b-a = 99a-99c = 99(a-c)

which is a multiple of 99 and it's positive since a > c

Edwin</pre>