;Task: Test whether an integer is even or odd. There is more than one way to solve this task: * Use the even and odd predicates, if the language provides them. * Check the least significant digit. With binary integers, ''i [[bitwise operations|bitwise-and]] 1'' equals 0 [[wikt:iff|iff]] ''i'' is even, or equals 1 iff ''i'' is odd. * Divide ''i'' by 2. The remainder equals 0 iff ''i'' is even. The remainder equals +1 or -1 iff ''i'' is odd. * Use modular congruences: ** ''i'' ≡ 0 (mod 2) iff ''i'' is even. ** ''i'' ≡ 1 (mod 2) iff ''i'' is odd.