This quote helps: "In fourteen-hundred-and-ninety-two, Columbus sailed the ocean blue."
If you can't remember that, just remember the year 1493. Should be a year before that.
1+4+9+2=16. And 1+6 = 7. 7 is much easier to remember than 1492. Work backwards from there.
1492 is 2 times 746. Or 4 times 374. I mean, 373. See how easy it is?
Remember back in 1992, when we had the Gulf War? Now just subtract 500 years. Wait--the war was in 1991? Make that 499 years. Or 501. Hmm.
If you know when the moon landing was, that would be an easy reference. You can do the math yourself.
1492? That's easy. Columbus, jackass.