How to use a tape measure

[Mister]

Haven't posted in a while but I was reminded last week that there are such things as dumb questions.

I'm searching for some cabinet for another customer when this normal looking, 30 or so year old man walks up to me holding a paper tape measure.

Him: Could you help me in a minute? I'm trying to measure the distance between the armrest (of a chair) and the floor but I don't know whether I'm doing it right.
Me: Sure, but how do you mean?
Him: Should I start at the zero or at the one?

Thankfully I was able to auto-respond "Start at the zero because the first centimeter counts as well", but wow.

[Raveni]

Back in the old days, many rulers didn't have a "zero" mark, and we would always start with "one", because you never knew how worn down that end of the ruler was. That first centimeter could be just a bit smaller, and throw everything off.

Of course, if you start with "one", you have to subtract one from the number you measure...

[Daemonmonkey]

Of course, if you start with "one", you have to subtract one from the number you measure...

"B-b-But-but I'm not good at that math thingie...?"