During their annual check-up at the memory clinic, three elderly friends were given a basic mathematics evaluation. The neurologist started with the simplest question possible to establish a baseline.
“Mr. Johnson,” the doctor began, “what do you get when you multiply three by three?”
“Blue,” Mr. Johnson responded without hesitation.
The doctor tried again with the second patient. “Mr. Williams, same question – three times three?”
“November,” Mr. Williams answered cheerfully.
With fading hope, the doctor turned to the final patient. “Mr. Peterson, surely you can tell me what three times three equals?”
“Nine,” Mr. Peterson said correctly.
“Wonderful!” the doctor exclaimed. “How did you figure that out?”
Mr. Peterson leaned forward and whispered conspiratorially: “Elementary, my dear doctor – I just took November and subtracted blue.”