Finite Mathematics covers a wide range of fascinating topics in math. One of my favorite topics to cover is linear algebra, and in particular, the use of matrices to solve systems of linear equations. One of the methods I cover is how to use inverse matrices to solve matrix equations.

An interesting application of inverse matrices is cryptography. You can create a message using a matrix along with a cypher that matches each letter to a certain number. Next you find the product of an encoding matrix and the message to encode the message. In order to decode the message, you must find the inverse of the encoding matrix, which is called a decoding matrix, and then find the left-hand product of the decoding matrix and the encoded message in order to recover the original message.

For the Cryptography Worksheet, each student was given an encoded message matrix and an encoding matrix. However, the encoding matrix on their worksheet was not the one used to encode their message. They must then work with the other students in order to find who has the correct encoding matrix for their message. This work sheet had them finding inverse matrices and finding the product of two matrices. After each student was successful decoding their message, they then had to answer all of the questions on their worksheet.