What is the reason for the impairment that prevents anyone from being able to calculate a 10% tip by moving the decimal point one digit to the left? Or adding half of this for 15% or doubling it for 20%?

Ok too hard...

Doesn't every handheld already have calculator? Is there an impairment about this too?

Yet these impairments may not interfere with programming a custom tip calculator.

Or maybe the impairment prevents programming too, so fiddle with AI to conjur an app...

But then why not skip the fiddling and simply tell google to figure the tip?

At such point something strange should happen:

Won't even a the very unobservant notice the pattern of moving the decimal point one digit to the left?!

Boggling.