Question

How can I add a two digit number and two three digit numbers in my head. Any tricks anyone knows in connection with short-cuts to solving different math problems( such as addition, subtraction,multiplication, division, rounding, conversions, percents) in your head when you can't use pencil, paper, or calculators.

Answer 1

Here is one site that may be of help. If this is not exactly what you were looking for, I suggest you go to www.google.com and type is math shortcuts and similar tag lines. There are many of these sites available for free. (Broken Link Removed)