Divisibility

https://en.wikipedia.org/wiki/Divisibility

Divisibility := If a and b are ints, then a divides b if b = a*n for some int n. a is called a factor or divisor of b. b is called a multiple of a.

• shorthand a divides b is a | b i.e. divisor | multiple

• (ab e Z AND b=a*n) . a | b

• int p is even exactly when 2 | p

• zero being even is a special case cuz zero is divisible by any int