Imagine you're a trader.



You're on the trading floor, trying to price out if a 15-year bond issued by General Electric will generate the returns needed to placate your investors.

Bad news, your calculator is dead and the trader from Cantor Fitzgerald is readying to signal his buy. What to do?

Well, if all you need to do is double the investment in five-years, you're in luck.

That's probably not the case, and maybe GE isn't issuing 15-year debt. But we compiled a list of eleven math tricks that might just come in handy at various times in life.

If you have a math trick you'd like us to add, leave it in the comments.

Eric Platt also contributed to this report.