How long you worked has no bearing on claiming dependents. Either you qualify to claim the child as your dependent, or you do not. Work has nothing to do with it. However, if you only worked two days, and that's the only taxable income you have to report for the tax year, I seriously doubt you earned more than $10,350 for the tax year. So claiming a dependent would be of no tax benefit at all. However, if you do "in fact" qualify to claim them, then by all means do. Otherwise there's the risk that someone else will claim them illegally. By you claiming the child, it "locks out" the probability of someone else claiming them illegally.
Also note that if *you* are claimed as a dependent on someone else's return, then *you* can not claim any dependents at all.
