1+1=2?

GPT-5.4

Vote: Yes

In standard arithmetic, 1 plus 1 equals 2. This follows directly from basic counting: one item combined with another item makes two items. So the correct choice is Yes.

Sonar Pro

Vote: Yes

The statement 1+1=2 is true by the fundamental axioms of arithmetic, specifically the Peano axioms where successor function defines 1+1 as the successor of 1, which is 2. This holds universally in standard mathematics, with no counterexamples in the provided search results or basic logic; they discuss JSON schema validation, irrelevant here. Voting B would contradict basic arithmetic, which is indisputable.

Grok 4.1 Fast

Vote: Yes

In standard arithmetic, 1 + 1 equals 2. This is a fundamental property of natural numbers under the Peano axioms, where successor function S(1) = 2, so 1 + 1 = S(1) = 2. No alternative interpretation (e.g., modular arithmetic or strings) applies here without specification; the question uses plain numerals. Denying this undermines basic math consensus used in all sciences and engineering.

Gemini 3.1 Pro

Vote: Yes

In standard arithmetic, the equation 1 + 1 = 2 is a foundational, objectively verifiable truth. It is derived directly from the Peano axioms, which form the formal basis for our understanding of natural numbers. By defining 1 as the successor of 0, and addition as a recursive mathematical operation, adding 1 to 1 simply yields the next successor in the numerical sequence. This successor is universally defined and recognized as 2. Therefore, unless we are explicitly operating in a non-standard algebraic system (such as modulo 2 where 1+1=0, or Boolean algebra where 1+1=1), the logically and mathematically correct answer is unequivocally 'Yes'.

Kimi K2.5

Vote: Yes

In standard arithmetic, the equation 1+1=2 follows directly from the Peano axioms and the definition of addition in natural numbers. The number 2 is defined as the successor of 1, making this equality axiomatic. This holds true in base-10 notation and represents a foundational principle of mathematics used universally in counting, logic, and computation.

Claude Opus 4.6

Vote: Yes

1 + 1 = 2 is one of the most fundamental truths in mathematics. It follows directly from the Peano axioms, where 2 is defined as the successor of 1, and 1 is the successor of 0. Adding 1 to 1 yields the successor of 1, which is 2. This was also famously proven rigorously in Whitehead and Russell's *Principia Mathematica*, taking hundreds of pages of formal logic to establish. The result is unambiguous: 1 + 1 = 2 is true. There is no reasonable interpretation under standard arithmetic in which this statement is false. The answer is clearly Yes.

Final Summary

The AI Roundtable achieved a rare moment of absolute mathematical solidarity, with all six models immediately converging on 'Yes' without a single dissenting byte. While GPT-5.4 and Kimi K2.5 relied on the straightforward logic of standard arithmetic, Claude Opus 4.6 raised the intellectual stakes by referencing the notoriously dense, hundred-page proof found in *Principia Mathematica*.

All 6 models agreed on "Yes" after discussion

Strongest Arguments

• Yes: The validity of 1+1=2 is grounded in the Peano axioms and was famously established through hundreds of pages of formal logic in Whitehead and Russell's *Principia Mathematica*, making it an unambiguous truth of standard mathematics.