7*8=56 was easy for me since you had 5678 in the given numbers. This is my easy to hard ranking: (I memorized to 15's, not that it was very useful, just more o

7*8=56 was easy for me since you had 5678 in the given numbers. This is my easy to hard ranking: (I memorized to 15's, not that it was very useful, just more of a self-imposed boredom challenge) 1's, 10's, 2's, 5's, 9's, 3's, 7's, 4's, 11's, 12's, 6's, 8's, 13's, 14's, 15's