I think you could greatly improve the readability of your game by highlighting the last column where the substraction happen. Then I feel like the game is a really boring task, with no timer and no time constraint it just feel like searching for the number 1 step from one of the number at the end of the list and just swapping it. It may happen that you have no other choice than loose the bonus with no real agency to what happen further down the line due to a lack of future insight to which number will appear where...
Perhaps having a mecanic where you have a limited time to make your choice and can choose between swapping, pressing equal or rerolling all the number (sort of a "pass") would be more addictive.
Some color touches would feel better too.