This puzzle says a man has five shirts and wears one every day for five days. How many shirts does he own?
The answer is still 5 shirts.
Wearing a shirt does not make it disappear. The statement already tells us exactly how many shirts the man owns: five.
The extra information about wearing one each day is there to distract you into thinking you need to subtract or somehow calculate a new total.
After five days, he may have worn each shirt once, or he may even have repeated some of them. Either way, the number of shirts he owns has not changed. He still owns all five.
