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In the Euclidean step $\gcd(a,b)=\gcd(b,a\bmod b)$, the remainder $a\bmod b$ becomes the new second argument of the pair. It replaces the original dividend $a$ in the next iteration.

Conditions: $a$ is a nonnegative integer.; $b$ is a positive integer.; The operation is the Euclidean step $\gcd(a,b)=\gcd(b,a\bmod b)$.

In the Euclidean step $\gcd(a,b)=\gcd(b,a\bmod b)$, the remainder $a\bmod b$ becomes the new second argument of the pair. It replaces the original dividend $a$ in the next iteration.

Conditions: $a$ is a nonnegative integer.; $b$ is a positive integer.; The operation is the Euclidean step $\gcd(a,b)=\gcd(b,a\bmod b)$.