Number crossword puzzles (or number fill ins) have gained popularity lately with people playing puzzle games on their phones and tablets. They provide the logical challenge you would expect from the puzzle genre, but don’t require the player to have the entire dictionary memorized to play.

With the demand increasing I thought I would provide some instruction on how to do so using Cross Digits.

If you’d like to play along on your phone or tablet you can download this puzzle for free.

iTunes App Store
Android Market

Starting the Game


  1. Open up the Easy Puzzle Select page.
  2. Let's try puzzle #1.
  3. Scroll over towards the given correct tiles.

The puzzle we’re going to look at is Easy #1. The numbers highlighted in green are correct! So let’s use them to figure out where we can place our next number.

Placing a Number


      1.  Open the 5 digit number list.


Notice the column highlighted on the board. It’s 5 digits long, and we know 2 out of 5. To open up the list of 5 digit numbers we just tap the “5” on the bottom bar.

      2.  Select “26468”.


Now we look for a number that will fit in this location. From what we’re given it starts with a 2. There’s only one number that fits that description, so it must be right! We can place it on the board.

      3.  Place it on the board by selecting the beginning tile and ending tile.


Checking the Number


  1. Hit the check button to see how you did. The game will lock correct tiles for you.
  2. Let’s open the 5 digit tab again to fill the number next to “26468”.
  3. Select a number that starts with “7-4--”.

How the check button scores.
New correct tile: +100 points
New incorrect tile: -50 points

The check button will highlight correct tiles green and incorrect ones red while updating the score. Let’s fill another 5 digit number on the board. You’ll notice that the game automatically disables numbers you’ve already used by fading them out, so you can narrow down the selection! Again there’s only one number that has the beginning “7-4--”.

Opening Up the Board


  1. If we fill this number it will make the others much easier, “---64---”.
  2. The 8 digit number list is much smaller but opens up more of the board for you.
  3. Now we know the starting 3 digits of 5 numbers!

There is a strategy in picking where to try to fill the board. Which spots will open up the rest of the board? By knowing more digits in a row you can solve the puzzle with certainty. This becomes especially important in the Expert puzzles. Very few correct tiles are given to you and some of the numbers listed may differ by only 1 digit!

Working Around


  1. Look at this 6 digit number.
  2. There’s no way to be sure which one on the list it is yet.
  3. Much easier now!

Sometimes you may get stuck in certain spots on the board. When this happens, work around! When you come back to that section of the board from another angle you will have more digits to work with. It is also possible to guess... but then there’s a possibility of not getting a perfect score. No one wants to see that happen!

Finishing Up


In no time you’ll be finished puzzle number 1. If you made no mistakes you’ll get a perfect score. 16900 is the perfect score for Easy #1.

I hope this helped you learn how to fill in a number crossword puzzle!
Feel free to post any questions or comments below.