I'm using octal as a sub-base to make it easier to count digits, just like using commas to group decimal digits. I think that still counts as binary tho!
I thought the finger counting system in that video wasn't particularly great (the solution for finger issues was a bad one, and four (I..) can easily be interpreted as a rude gesture) but the mental maths systems were cool
wow i cant believe nobody else pointed this out but today someone on discord informed me that I accidentally misplaced a bit when multiplying 10 by 101. According to this chart, two times five is eighteen.