> For the complete documentation index, see [llms.txt](https://computational-thinking-in-room11.gitbook.io/room-112-dhs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://computational-thinking-in-room11.gitbook.io/room-112-dhs/problemsolving/problem-6.md).

# Problem 6

Crypto-Arithmetic (aka Eliminating Possibilities to keep a secret)

Basic Rules:  Each letter represents a single digit (0-9).No two letters can represent the same   digit. All A's will have the same value.

Example: Robert is a secret agent in New York City running from the KGB. He needs to communicate a message to his  FBI handler and uses the crypto-arthemtic system the worked out by sending the following text message:

```
TOM was riding in a CAB filled with BOAS!
```

When Madeline (his handler) receives the message she has 15 minutes to decipher the message and locate the document at the right address 

![](https://2507214486-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LpUPSf3tCxHePJxNjfg%2F-M-ArTHlTYChani3gXbO%2F-M-ArrMogKxS61AcSp4W%2Fanimated-taxi-image-0017.gif?alt=media\&token=855f2676-c0a1-405d-8b3a-0a5f41b6314c)

```
  T  O  M +   C  A  B    =    B O A S  
```

What are the possible solutions?

{% file src="/files/-M-AmaaifQrsXIl2NKWP" %}
Sample Solution - Open at Your Own Risk
{% endfile %}