Question: A man was born on January 1st, 23 B.C. and died January 2nd, 23 A.D. How old did he live to be?
Answer: 45 years old.
There is no year 0 so you can add 23 to 23 but you must subtract one to take year 0 out of consideration: 23 + 23 - 1 = 45 years old. In some cultures people are born 1 years old, in this case they would be 46 years old when they die.
Question: I'm 10 years old my brothers half my age now I'm 100 years old how old is my brother now?
Answer: 95 years old Because he's half my age when I was 10 so he's 5 years old so I'm only 5 years older 100-5=95