You do not have to write the claims to pass the exam. You would have to recognize bad claims from good claims to pass. There may be 5-6 questions on claim examination. The most things about claims you would know is difference between "consist of", "comprise", "consist essentially of", how to spot a jepson claim, a markus claim, multi-dependent claim and whether a multi-dependent claim depends on another multi-dependent claim, etc. You can just spend lunch hour writing something really simple, like a pencil, a desk, a cup, or whatever nearby to get familiar with the jargons and structures of claim writing. A typical question would have a claim, say, temperature at least 40 degrees, and ask you whether another claim which is claiming a temperature of 60 would infringe. Really simple stuff. As I remember, they have not done a question with claim counting for quite some time so you may want to pay attention to the sure fire method and claim counting.