Kunlik Sinov

Qonuniyatni aniqlab so'roq belgisi o'rnidagi sonni aniqlang.

$t\otimes n=t+n$   $\Rightarrow \left(\mathrm{<mn>4</mn>}\otimes \mathrm{<mn>7</mn>}\right)\otimes \left(\mathrm{<mn>8</mn>}\otimes \mathrm{<mn>5</mn>}\right)=?$