The touchpad. The pad under the screen controls the pointer: swipe on it to move the pointer around, press its edges to move the cursor one step (they act as arrow keys), and click its center to select. On graphs, lets you drag points and objects directly.

Fixing typos. Press the touchpad edges to walk the cursor through what you've typed, and press to delete the character to its left. There is no insert mode to switch on: the entry line always inserts, so new characters slide in at the cursor. (clear) wipes the whole line, and (undo) takes back your last edit.

Dialog boxes. Many tools open a small form first: creating a matrix asks for the number of rows and columns, and every distribution and test command collects its inputs this way. jumps to the next field and goes back — don't arrow between fields, because in a number field decreases the value instead of moving on. Press to accept the whole form, or to back out. Sizing a 3 x 3 matrix, for example, is just .