In this autocad tutorial we will draw a simple washer using circle tool.
1. Open a new drawing. Click New 
2. Type z [Space bar], e [Space bar]. This will zoom extents your drawing area.
3. From the ribbon tools, click CIRCLE
4. Specify center point of the circle at 0,0. Type 0,0 [Enter]
5. Look at command line, it showing input in radius mode;
to enter input in Diameter mode, type D [Enter].
6. Type 2 for inner diameter [Enter].
7. From the ribbon tools, click CIRCLE.
8. Make sure Object Snap Tracking is ON (1) and snap to center is active (2).
9. Now point your cursor at center point of the last circle. When your cursor snap at center, click to define center of new circle.
10. Look at command line, it showing input in radius mode;
to enter input in Diameter mode, type D [Enter].
Type 4 for inner diameter [Enter].
Your washer is done.
11. Press [Esc] key few times to end circle command.