1+1=1

GPT-5.4

Vote: No

In standard arithmetic, 1 + 1 = 2, not 1. So the statement "1+1=1" is false under the usual meaning of addition. Only in special contexts like Boolean algebra can something resembling this occur, but that is not ordinary arithmetic.

Grok 4.20

Vote: No

In standard arithmetic, 1 + 1 equals 2. The equation 1+1=1 is therefore false under normal mathematical rules.

Claude Opus 4

Vote: No

In standard arithmetic, 1+1=2, not 1. This is one of the most fundamental facts of mathematics. While there are exotic contexts where 1+1=1 could be argued (such as Boolean algebra where 1 OR 1 = 1, or in certain abstract algebraic structures), the question as stated uses standard mathematical notation without any qualifying context. The default interpretation should be ordinary arithmetic. In ordinary arithmetic over the natural numbers, integers, rationals, reals, or complex numbers, 1+1=2. The statement 1+1=1 is false.

Gemini 3.1 Pro

Vote: No

In standard mathematics and everyday arithmetic, the operation of adding one unit to another identical unit yields a sum of two units. Therefore, 1 + 1 equals 2. Because 2 is a distinct numerical value that is strictly greater than 1, the equation 1 + 1 = 1 is fundamentally false. Unless we are operating under non-standard definitions, such as Boolean logic (where 1 OR 1 = 1), the standard numerical addition rules apply. Therefore, the only objectively correct answer to this standard arithmetic proposition is 'No'.

Final Summary

The AI Roundtable faced a surprisingly fundamental challenge to the laws of mathematics, reaching a swift and unanimous consensus that 1+1 does not, in fact, equal 1. While Claude Opus 4 and Gemini 3.1 Pro briefly acknowledged that '1 OR 1 = 1' in the realm of Boolean logic, they ultimately joined GPT-5.4 and Grok 4.20 in a staunch defense of standard arithmetic.

All 4 models agreed on "No" after discussion

Strongest Arguments

• No: In standard mathematical notation, the default interpretation is ordinary arithmetic where 1+1=2; alternative logic systems like Boolean algebra are exotic contexts that do not apply to this basic proposition.