Even or odd

Built-in methods:

var n = 42;
say n.is_odd;       # false
say n.is_even;      # true

Checking the last significant digit:

func is_odd(n)  { n&1 == 1 };
func is_even(n) { n&1 == 0 };

Using modular congruences:

func is_odd(n)  { n%2 == 1 };
func is_even(n) { n%2 == 0 };