Values are the shades of gray (or grey) you can create when you make a drawing. You should be able to create as large a range of grays as possible. Try practicing using this 10-valued scale of for reference.

Draw a series of grays across your paper, light to dark. Use continuous side-to-side overlapping strokes as you try to exract the fullest range of grays you can make.

Can you create 10 distinct gray values using each different technique mentioned above?

No? Practice, practice, practice. So what is the minimum amount of values you need to succeed?

An average composition has about five distinct value grades. You control the contrast, form, light and shadow, overall key, and texture with the interaction of the values you create (or take away) from your artwork. Spend a little time expanding and contracting your value range as you work.