Headings are not part of the Array

gradeTable (what is actually in memory)
99	42	74	83	100
90	91	72	88	95
88	61	74	89	96
61	89	82	98	93
93	73	75	78	99
50	65	92	87	94
43	98	78	56	99

The row and column numbers are not part of the array. They are usually shown in pictures of an array, but the array object does not explicitly contain the indexes. When you ask for

gradeTable[ 5 ][ 3 ]

Java knows what cell you mean and goes there directly.

More Important Stuff:

Rows are numbered from 0 to N-1, where N is the number of rows
Columns are numbered from 0 to M-1, where M is the number of columns.
A 2D array with N rows and M columns per row will have N times M number of cells.
However, it is possible for a 2D array to have a different number of cells in each row.

Details about these issues will follow.

QUESTION 4:

With the example array, will the following statement work?

gradeTable[7][2] = 82 ;

99	42	74	83	100
90	91	72	88	95
88	61	74	89	96
61	89	82	98	93
93	73	75	78	99
50	65	92	87	94
43	98	78	56	99

99	42	74	83	100
90	91	72	88	95
88	61	74	89	96
61	89	82	98	93
93	73	75	78	99
50	65	92	87	94
43	98	78	56	99

99	42	74	83	100
90	91	72	88	95
88	61	74	89	96
61	89	82	98	93
93	73	75	78	99
50	65	92	87	94
43	98	78	56	99