2
Input: 1 → [?] → 0, what is the rule? =
3
Input: 5 → [?] → 10, what is the rule? =
4
Input: 5 → [?] → 15, what is the rule? =
5
Input: 7 → [?] → 14, what is the rule? =
6
Input: 3 → [?] → 0, what is the rule? =
7
Input: 9 → [?] → 6, what is the rule? =