Number Scrabble - the Game (aka: Math Scrabble)

"Number Scrabble" (or "Math Scrabble") is a game based on normal Scrabble, but you make equations instead of words. The letter tiles used in Scrabble are replaced with numbers and operators. You can use a standard scrabble set to play number scrabble by writing the proper numbers and operators on the back of the standard scrabble tiles. Like regular Scrabble the game is great for ages 8+.

------ an aside for the experienced game player ------
Sick and Tired of ordinary Scrabble? I'll bet you are. We all know why, too. It's "that friend". You know the one. It's game night and sooner or later you are reminiscing about games you played as a child with your grandmother, and someone foolishly pulls out the Scrabble. For a move or two it's warm and fuzzy like you remember. Then "that friend" plays "toea" connected with "aa". You're like: "umm, what is that?" You want me to kick your butt-a with my foot-a? and "aa"? oh right its some onomatopoetic rock from hawaii - isn't that a hawaiian word though? your "friend's" next move? "tsktsks". excuse me that is not a word! next? "suq". yes, yes it does. for all of us. At this point, everyone is fully jolted out of their sentimental stupors and remembering why Scrabble is so pointless and they are never ever ever going to play it again. Even in nerd circles, if the best thing you can do with your time is to memorize some utterly arbitrary list of 170,000 meaningless letter sequences so you can ruin a perfectly fun game for all your friends - well, that makes you a major toadstool not an erudite intellectual. Who came up with that arbitrary list anyway? Wikipedia tells me it was the "National Scrabble Association Dictionary Committee". Well, sounds to me like a bunch of pencil pushers came up with a hazing ritual of epic proportions.

Anyhoo, this sort of scarring experience got me thinking. Perhaps we can do away with the silly nonsense of fabricated letter sequences that must be memorized? You may also have smart friends that really don't speak english so well, at that point the arbitrariness of the default Scrabble letter sequences seems even more glaring. Considered this way, it seems painfully clear that we should replace all that gobbledygook with a universal language that has a simple, well known character sequencing structure. MATH - duh! With math as our language, everyone knows the rules, and everyone knows what sequences are valid. You could sit down for game night with aliens from another planet, and everyone would be with the program*. Now that is a nerdy game worth playing.

* well, this game uses decimal numbers, which of course any alien would understand but you'd look a bit provincial if you were not able to do anything else. try a few games and then consider leveling up with Binary Number Scrabble.

Step 1: Make Your Tiles

To play "Number Scrabble", you need a game board and tiles. Coincidentally, it is very easy to retrofit your existing Scrabble kit. You just need to relabel all the tiles.

If you've seen the light, just grab a sharpie and you can write on the backs of all the tiles directly. If you want to give it a test first, you can put masking tape on the tiles and write on that.

If you are going to play with young children, you can change the Square and Square root tiles to Plus and Minus.

Number/Operator	How Many	Score value
1	5	1
2	5	1
3	5	2
4	5	2
5	5	3
6	5	2
7	5	4
8	5	2
9	5	2
0	5	1
+ (add)	7	1
- (subtract)	7	1
× (multiply)	5	2
÷ (divide)	5	3
² (square)	2	3
(square root)	2	3
= (equals)	20	1
blank	4	0

Step 2: The Rules

Except as noted, game play is similar to normal Scrabble
On each turn, players must make or add to a valid and correct equation.
Players keep 9 tiles in their hand at all times, not 7 as in normal Scrabble
Players form valid equations rather than words.
- example: '3+3=6'
You can add to an existing equation on one side or both sides in a single turn.
- example: you can add to both ends of '3+3=6' in a single turn to make '63+3=66'
You may only use one new '=' sign per turn
Order of operation: The game will function correctly as long as you agree beforehand on the order of operation. You can play with either "standard math" (ie, multiply preceeds plus unrelated to the written order), or "strict left-to-right evaluation".
- Square and Square-root operators apply only to the immediately preceding or following number
- There is no implied multiplication
Equations can have multiple equal parts.
- example: '2x2=1+3=4=5-1'
Redundant equations are valid
- example: '1-1+1-1=0=0+0'
The '-' may be used either as an operator or before a number indicate its sign.
- example: '-3=5-8'
- example: '3=-5--8'
You may not use leading '+' signs or leading '0' in front of a number
You may not string together arbitrary symbols
- example: '3+xx4==12' is NOT valid.
In normal scrabble, you can place one word alongside another if they create a valid cross-word. Here, a 2-character sequence can never be an equation so this generally is not possible. As an optional rule, you may choose to allow placing alongside when only numbers are formed as the cross-words, but you still need to connect to an existing equation some other way.
As an optional rule, you may choose to disallow the following "Identity" equation fragments:
- "x1" example: you could not turn '3+4=7' to '3+4=7x1'
- "+0" and "-0". example: you could not turn '3+4=7' to '3+4=7+0'
- I recommend allowing these when playing in a learning scenario, but disallowing them with experienced players as you get into tedious '2+2=4+0+0+0x1x1' situations.

Step 3: Scoring

Unlike Scrabble, when adding to an existing equation only the newly added tiles score points.
double-letter, triple-letter, double-word, triple-word squares work as usual
All equations earn a bonus depending on the actual numeric value of the equation. This rewards equations of high value like '25x25=625' compared to ones of low value like '1+1+1+1=4'.
- The calculation of the bonus is based on the equation value as follows:
- The result is the bonus, which is added to the equation score before applying any double and triple word scores.

example: '2+2=4'. equation value = 4. absolute value of that = 4. square root of that = 2. round up to get bonus points = 2.
example: '3+3=6'. equation value = 6, absolute value of that = 6, square root of that = 2.45, round up to get bonus points = 3.
example: '3-20=-17. equation value = -17, absolute value of that = 17, square root of that = 4.12, round up to get bonus points = 5.

When a player goes out, add to their score the sum of the unplayed number tiles.

Step 4: Game Play

See photo sequence below for a typical game with some score calculations annotated.

Credits: my dad, who invented this game as a child and managed not to lose his original tiles.