It doesn’t ask you to subtract the numbers, but to calculate the distance (i.e. the absolute value of the subtraction). So depending on which numbers are paired up, the sign of the pair can be different.

HiPER Calc Pro. A great scientific calculator I use constantly. (There is also a unpaid, ad-supported version, and the ads weren’t too intrusive the last time I tried it)

My router is called Jupiter, everything connected to it is named after a moon. Callisto, Ganymede, Thelxinoe, Kallichore are what I’m currently using.

That’s why I don’t let every device decide individually. I know my router (FritzBox) prioritizes the pi-hole (it’s even called “preferred” and “alternative” DNS-Server in the UI)

I have my pi-hole setup as the upstream DNS in my router, with cloudflare as a secondary DNS. That way, all my devices always use the router for DNS (since that’s what is advertised in my DHCP) and the router then uses pi-hole if it’s available, or cloudflare if it isn’t. But the individual device doesn’t get to choose between different servers.

Matlab

Incandescent oven bulbs will probably not be replaced, simply because there is no reason for it. The “wasted” energy from an incandescent bulb is expelled as heat, and extra heat in an oven is not a problem. You can describe the bulb in an oven as a tiny heater that just happens to give off a bit of light.