One shot is one unit.
One beer is 2-3 units.
One glass of wine is 2-3 units.
It is very simple maths. The kind you find hard to mess up when drinking.
One shot is one centilitre.
One beer is 2-3 centilitres.
One glass of wine is 2-3 centilitres.
It's not maths at all, it's just communication. There's nothing "simpler" about "unit" than "centilitre", it's just less clear.
It would be like a continental European going to America and going, "What are all these MILES things? It's confusing!".
One shot is one unit.
One beer is 2-3 units.
One glass of wine is 2-3 units.
It is very simple maths. The kind you find hard to mess up when drinking.