Lesson 12.1 – Adding and Subtracting Matrices Take notes in your notebook. Work the problems in your notebook BEFORE advancing to the solutions.

 A matrix is a rectangular arrangement of numbers into rows and columns This is a 2 by 3 Matrix.

2 Rows and 3 Columns

 Matrix - a rectangular array of variables or numbers in horizontal rows and vertical columns enclosed in brackets.  Element - each value in a matrix; either a number or a constant.  Dimension - number of rows by number of columns of a matrix.  **A matrix is named by its dimensions.

Dimensions: 3x2 Dimensions: 4x1 Dimensions: 2x4

3 x 3 3 x 5 2 x 2 4 x 1 1 x 4 (aka: square matrix) (aka: row matrix) (or square matrix) (aka: column matrix)

Column Matrix – a matrix with only one column. Row Matrix – a matrix with only one row. Square Matrix – a matrix that has the same number of rows and columns.

1.) Add the corresponding elements of each matrix.

To add two matrices, they must have the same dimensions. To add, you simply add corresponding elements. Answer Matrix Working matrix

Matrices can only be added if they have the same # of rows & columns 2 x 32 x 2

7 = = Working matrix Solution matrix

 1.)  Subtract the corresponding elements of each matrix.

To subtract two matrices, they must have the same dimensions. You simply subtract corresponding elements. Working matrix Solution matrix

= (-1) (-4) = Working matrixSolution matrix

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 Read Lesson 12.1 “Adding and Subtracting Matrices” in your textbook and review the Power Point lesson again.  Complete the 12.1 Vocabulary Worksheet  Review and complete the 12.1 Reteaching Worksheet

In your textbook:  Lesson 12.1/ 7- 17odd, 19-29

Jim, Mario and Mike are married to Shana, Kelly and Lisa. Mario is Kelly’s brother and lives in Florida with his wife. Mike is shorter than Lisa’s husband. Mike works at a bank. Shana and her husband live in Kentucky. Kelly and her husband work in a candy store. Who is married to whom? Shana Kelly Lisa Jim MarioMike X X X OX XO XO