Once you unlock the boat, you can unlock the number problem. Just get in the boat for this step.

Just put one finger or toe or nose on the Enter key on your keyboard. Then use a finger or toe or your other nose to press the Backspace key 55 times. (On a game pad, hold A and hit B.)

Have fun with this super amazing puzzle! At least it's not a $1.99 IAP!

You don't need to beat the puzzle to get the achievement. Simply close out and go about your day. You might get it after a battle or after you close Final Fantasy, but it'll pop.