$25+37\equiv \_\_\_\_\_\_$  mod12

Congruence: Let $a,b\in Z$  and $m\in n$ . We say ‘$a$ ’ is a congruent to ‘$b$ ’ modulo ‘$m$ ’ and write as $a\equiv b$ mod$m$ , if ${{}^m|}_{a-b}$ . The integer $m$  is called the modulus of congruence.

$62\equiv x\left(\mathrm{mod}12\right)$

$\frac{62-x}{12}$

If $x=2$

$\frac{62-2}{12}=5$