A Play Play Learn Guide to Teaching and Learning
Secret Code 13+4
About the Game
Players: 2 - 4
Age: Elementary
Time: 15 min.
Subject: Math
Jürgen P. Grunau and HABA created Secret Code 13+4 as a robust math game carefully
concealed behind an attractive theme of secret agents breaking into a museum to steal the mask of Amun
Re. To be successful here, though, players will have to use some serious math skills. The game is built
around the mechanism of reaching target numbers given a pool of starting numbers – in this case,
starting numbers from rolled dice – manipulated by any desired mathematical operations. As with word
games, where players are scrolling through their mental vocabulary lists to find words that match given
letters, in Secret Code 13+4 players are playing with numbers in their mind trying to find combinations
to hit the target on the lasers blocking their path.
The dice in Secret Code 13+4 are not
regular dix-sided dice. Instead, these
custom dice offer numbers up to nine for players to use in their math operations. As dice are used to
crack the codes and deactivate the lasers, they are set aside. The goal then is to find efficient operations
that make use of the fewest possible dice for each barrier thereby letting a player advance more quickly
than others as they all race towards the treasure. Diverging paths on the board also offer another decision
point for players; which path of codes might be easier?
The Math Behind the Game
To extend the math beyond the game, have players figure out which numbers are easier to
unlock. Think about the factors involved in the unlocking process. Codes one through
nine can be unlocked with a single die showing the desired number. But what about
other numbers?
Educational guide created by
Christopher Harris
Brian Mayer
Editorial Director
Design & Development
[email protected]
[email protected]
Patricia Harris, PhD
Curriculum & Instruction
[email protected]
Are some target numbers easier to
crack? Numbers like 12 or 18
have multiple factors: 2x6 and
3x4 for 12, 2x9 and 3x6 for 18. 13, being a prime number, only has itself
and 1 as possible factors; reaching 13 will have to involve addition and
subtraction. The code tiles go up to 18, but the higher numbers offer
fewer opportunities for addition and will likely require multiplication along with
addition and subtraction. Code 18 has only one possible addend pair, two dice showing 9s; 12 on the
other hand can be unlocked with 4 sets of addend pairs, 3+9. 4+8, 5+7, or 6+6. Have fun on a first play
through, but for later games encourage
players to think strategically using
Variations to Extend Play
probability to inform their decisions.
The rules as written let players add, subtract, multiply or divide the numbers from the dice to reach the
code. Today, math instruction often introduces the concept of square numbers in primary grades. Square
numbers can be easily represented visually with Cuisenaire number rods or
cubes. Squaring a number means putting down the same number of rods
across as the rod is tall so that the rods form a square. For example to form
a square with the light green rod three units in length, we would need to
use three
rods. If we then count the units in the square, three sets of three, we find
that three squared is nine.
You can introduce squaring as a new operation in Secret Code 13+4. Squaring will only work with the
smaller numbers as the operation will take anything above 5 squared (25) well out of range of the
highest target number of 18. For rolls of
two through four, however, squaring
Making the Game Work
offers a different way to use a single die
to efficiently reach higher values.
Assessing Learning
Assess mathematical operations:
1) Pick three lasers and offer pre-set dice that can be
used to reach the three targets. Increase difficulty as
needed to challenge different levels of learners.
2) Have students roll the dice and then identify at
least three different ways to reach a target number.
Bonus points for most dice and fewest dice used.
3) Create a worksheet showing combinations of three
dice, have players list three reachable targets for each
set of dice explaining the operations involved.
Secret Code 13+4 works beautifully in many
different instructional situations. With fast setup
and easy rules, players can get started quickly. The
game takes about 15 minutes to play, a nice length
of time for a mini activity after a lesson for a large
Play Play Learn provides educational resources and consulting
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This guide ©2014, Christopher Harris. Secret Code 13+4 ©2012,
Habermass Corp., Inc. aka HABA.