Moving the cursor with the keyboard

The behavior of the arrow keys is the usual one as long as we are working within pieces of text, but it is modified near symbols. Let us see an example of cursor movement in a fraction.

Initial state; cursor in the denominator
Pressing the left arrow key behaves as usual, since we move within the denominator, which is made up by text
However, pressing again the left arrow key moves the cursor to the numerator, as if instead of a fraction we had two lines of text
Pressing the down arrow key moves the cursor to the denominator
Pressing the right arrow key moves the cursor after the fraction; note the change of size of the cursor, indicating that it is affecting the whole fraction
Pressing the delete key selects the whole fraction, instead of deleting one character; if we pressed delete again, the whole fraction would be deleted.

This behavior can be a little bit confusing when first met; if at some point it seems you cannot exit from a power, click with the mouse where you want to go, or just keep pressing the right or left arrow keys until you exit from the problem area.

We can select text by holding down the shift key while we move the cursor with the arrow keys, or by pressing down the mouse left button at one end of the contents to select, moving it to the other end, and releasing the button. Pieces of formulae can be cut, copied and pasted as expected.