The symbols next to the numbers change every time you click play again...if you go down every row and subtract from the number you pick what the number added together equals the symbol wil always be the same for every number you pick.....for example if you pick 99 its 99-18which is 81 . of course you get the 18 by adding the two numbers of the original number together..9+9=18. If you go down the row without hitting play again you will see that every number picked will have the answer of the same symbol..when you click play again they change but again if you do the math on every number on the board you will see the answer is the same symbol.