Question 1074564
9 is odd.  If middle number is n, then the first four are n-4, n-3, n-2, n-1.


{{{(n-4)+(n+4)+(n-3)+(n+3)+(n-2)+(n+2)+(n-1)+(n+1)+n=90}}}

{{{9n=90}}}

{{{highlight_green(n=10)}}}------the middle number



The highest of the nine numbers is {{{n+4=highlight(14)}}}