I'm going to teach you how to scratch-draw a calculator or something else. Things like your cellphone (I wouldn't do that), your psp (I wouldn't do that) or your Xbox 360 (no I neither would do that)
Step 1: Materials
Al these materials and tools are household products, maybe you don't have them but there not hard to get (unless you live in Canada).
The tools and materials you need are:
a lot of tape
image of something you want to make
a little knife
something to scratch in
gloves might be useful since your working with a knife, even when your not afraid of cutting yourself (jackass!), you have to put a lot of pressure on the back of the knife, this can hurt when you have a complicated image.