Congruence Modulo Integer/Examples

Congruence Modulo $20$: $100 \equiv -40 \pmod {20}$
=== Congruence Modulo $12 \, 345 \, 678$: $12 \, 345 \, 678 \, 987 \, 654 \, 321 \not \equiv 0 \pmod {12 \, 345 \, 678}$ ===