The Magic Number 7

This test is known in psychology as the Digit Span Test. In 1956, cognitive psychologist George Miller published a famous paper arguing that the capacity of human short-term memory is approximately 7 items, plus or minus 2.

Improving Your Score with Chunking

If you find it hard to remember more than 7 digits, try chunking. This is the process of breaking a long string of numbers into smaller groups.