In ClarisWorks 1.0 and 2.0, pressing the left or right arrow keys while entering data in the data entry bar of a spreadsheet document would select the cell to the left or right of the current cell.
In ClarisWorks 2.1, using the arrow keys while entering data will move the cursor to the previous or next character in the entry bar, similar to the way text entry works in a word processing document. To move to the adjacent cell, hold down the Option key while pressing the left or right arrow key. Or press the Enter key to enter the data and then you can use the arrow keys to move to adjacent cells.