From mnemonic and memory to math and mental calculation
You could be better at doing math than you might think. There are methods that allow one to do tricks with numbers that seem just across the street from flat out impossible.
Watch as Arthur Benjamin shows us how one can calculate in ones head, sometimes faster than one could use a calculator.
Approximately 10 minutes and 42 seconds into that first video, he uses some variant or another of the major system in order to hold some numbers in his mind, while he works on others. Have a look at the major system and how it works.
Finally, Arthur Benjamin shows us how to do a couple of mental math methods. The tricks are surprisingly easy to use. Impress your friends and scare your neighbors!