Extensive and intensive parameters

Consider two thermodynamic systems $𝑆 1$ and $𝑆 2$ with parameters $𝐸 𝑖, 𝑇 𝑖, 𝑉 𝑖, 𝑝 𝑖$ , &c. An extensive parameter $𝐸 𝑖, 𝑉 𝑖$ is additive if the two systems are combined. An intensive parameter $𝑇 𝑖, 𝑝 𝑖$ remains unchanged if a single system is doubled, i.e. cloned and brought into thermal contact with its clone.