Brilliant response Mark! Love it! And if anyone wants to know a source for 7-+2 can be found in psychology journals. Here is an example:
“In the past, the quantification of limited working memory capacity, as the “magic” 7 ± 21, has fundamentally influenced the fields of psychology and cognitive science.”
Source:The Capacity of Cognitive Control Estimated from a Perceptual Decision Making Task
Tingting Wu,1 Alexander J. Dufford,1,2 Melissa-Ann Mackie,1,3 Laura J. Egan,1 and Jin Fana, 2016, in NATURE, Science Reports.
Enjoy, Gina