Two integers a and b are congruence modulo n if they differ by an integer multiple of n. That a - b
=
kn for some integer k.
This can also be written as a ≡ b (mod n). Here the number n is called modulus . In other words,
a ≡ b (mod n) means a - b is divisible by n.
This application is very useful to find the weekdays name after a given number of days
9Apps 4.9
