In "делегация из 5 человек во главе с президентом", are 5 or 6 visitors meant?

Question

Got a business letter with this phrase followed by a list of 6 officials, sixth being a president. So I wonder whether it's me who always interpreted this phrase incorrectly (5 members total) or them (6 members)?

Answer 1

Well, this is exactly why the words like "включительно", "включая" do exist - otherwise in some cases there is indeed a disambiguation. The answer to your question is that the phrase "делегация из N человек во главе с президентом" can mean either N or N+1.

To avoid such uncertainty one can say:

• Делегация из пяти человек вместе с президентом
• Делегация из пяти человек и президент
• Делегация из шести человек, включая президента
• Делегация из пяти человек, не включая президента

Answer 2

It's them, and it doesn't look like an intuitive kind of mistake: by which I mean, it was likely caused by uninformed overthinking on the part of the person that wrote the letter.