this formula; =ROUNDUP(RAND()*(89-1)+1,0)
will provide the number(s) you seek, but Excel will generate a new random number each time the sheet recalculates, so I'm not sure how you'd keep track of them, on the sheet, without a macro.
The RAND() function generates a random number between 0 and 1.
Info here, for assistance;
I've incorporated the "roundup" function into what I've suggested to give whole numbers.
Hope this helps.
I'm a bit rusty with macros... see if you can manage with what's above, to be going on with.