Combinations of { 1, 2, 3 } and { -4, -5 }:
1 * -4 = -4
1 * -5 = -5
2 * -4 = -8
2 * -5 = -10
3 * -4 = -12
3 * -5 = -15

Unique triples of { 1, 2, 3, 4 }:
1 * 2 * 3 = 6
1 * 2 * 4 = 8
1 * 3 * 4 = 12
2 * 3 * 4 = 24