Mathematics is the foundation upon which all science is built.

Never use a credit card for credit. The only kind of credit， or debt， that is acceptable is debt to acquire something whose exchange value is extremely likely to increase， like in a home. The exchange value of most things diminishes or vanishes the moment you purchase them. Don’t be in debt to losers.

The two most important days in your life are the day you are born and the day you find out why.