

Sure , this is neat, but counting single digits on digits is easy for people.
Mentally adding 16 to 8 and 4 is where people will find this more complex, especially if you have easy stuff like 7+5, you have to do the math in your head to move it from 4,2,1+ 4,1 to 8,4.








I have the gene where my second thumb joint/knuckle near the base doesn’t bend. I can only count to 10 using this method. 11 and 12 are not really reachable. Even 9 is a bit of a stretch.