Modular
$$ a \equiv b \;(mod\; m) $$ where a and b are integers, and m is a natual numebr N
Examples
Let's loko into 1st examples: $$ 10 \equiv 4 \;(mod\; 6) $$ can be intrepreted as 10 - 4 is divisible by 6,
$$ 28 \equiv 4 \;(mod\; 6) $$ can be intrepreted as 28 - 4 is divisible by 6,
$$ 36 \equiv 0 \;(mod\; 6) $$ can be intrepreted as 36 - 4 is divisible by 6.
We can see that two different numbers can be represented as congruent in mod 6. Notice above that both 10 and 28 are congruent to 4 in mod 6.
Moduler 2
Moduler 2 arithemtic example