So you want to use bc for some hexadecimal maths. You set the input base:
ibase=16
and the output base:
obase=16
Oops! I just set it to output in base 22. I’d already set it to think numbers were input in hexadecimal, and that’s how it handled the “16” in my obase command. Either do this:
ibase=16 obase=10
Or this:
obase=16 ibase=16