Stupid Question about ABV

Okay so, I’ve always wondered how ABV is actually measured… say I drank 5 beers that come in at 6% but they’re 500ml.

But the 350ml bottles of the same beer is also 6%, I may sound dumb here but in theory would the affects/alcohol intake be the same if you drank the smaller ones because they’re both 6% in volume.

Sorry for my stupidity here, just never understood how abv actually works.