With Mouse Keys on your Mac, you can move the mouse pointer and press the mouse button using the keyboard or a numeric keypad. To use Mouse Keys, choose Apple menu 
> System Settings, click Accessibility 
in the sidebar, click Pointer Control on the right, then turn on Mouse Keys. (You may need to scroll down.)
The following illustration shows the keys to use on a keyboard (the keys on the left) and on a numeric keypad (the keys on the right) when Mouse Keys is on.
Note: When Mouse Keys is on, you can’t use the keyboard or a numeric keypad to enter text.
- Move the mouse pointer:
With a numeric keypad: Use the 7, 8, 9, 4, 6, 1, 2, 3 keys on the keypad.
With the keyboard: Use the 7, 8, 9, U, O, J, K, L keys. - Click a mouse button:
With a numeric keypad: Press 5 on the keypad.
With the keyboard: Press I. - Press and hold the mouse button:
With a numeric keypad: Press 0 (zero) on the keypad.
With the keyboard: Press M. - Release the mouse button:
With a numeric keypad: Press “.” (period) on the keypad.
With the keyboard: Press “.” (period).