Texas Instruments TI-89 Manual Book page 5

The 64 columns are labeled A through BL. Rows are numbered
1 through 999. Although you may insert and delete columns and
rows, columns will always be labeled A-BL and rows will always
be numbered 1-999. You cannot change the alphabetical column
labels or row numbers.
Individual cells are referred to by their column letter and row
number. For example, B25 refers to the 25th cell in column B.
Cell ranges are separated by a colon. For example, A1:C5 refers
to the rectangular range that has the 1st cell in column A as its
top left corner and the 5th cell in column C as its bottom right
corner.
Spreadsheet
name
Row number
TI-89 / TI-92 Plus / Voyage™ 200 PLT CellSheet™ App
Column letter
Edit line
Page 5