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"array" was my general variable name for an array in my example. You of course would use the name of your variable. Common sense!

I just told you why. You have declared myNumbers as a 2D array.

Simple answer: you need two indices to access an element (array[x][y]).
Long answer: a 2D array is a 1D array of 1D arrays. So each...

myNumbers[i]=sc.nextInt();

You have declared myNumbers as a 2D array but are trying to use it like a 1D array.