Congruence Modulo Integer/Examples/100 equiv -40 mod 20

Example of Congruence Modulo an Integer

 * $100 \equiv -40 \pmod {20}$

Proof
By definition of congruence:
 * $x \equiv y \pmod n$ $x - y = k n$

for some $k \in \Z$.

We have:
 * $100 - \paren {-40} = 140 = 7 \times 20$

Thus:
 * $100 \equiv -40 \pmod {20}$