A __ matrix__ is an array of numbers.

The horizontal lines of the matrix are called ** rows** and the vertical lines are called

**. The numbers in the matrix are called**

__columns__**.**

__elements__The **size** of a matrix is determined by how many rows and columns are in the matrix. A matrix with ** m** rows and

**columns is called an**

*n***x**

*m***matrix, where**

*n***and**

*m***are the**

*n***of the matrix.**

__dimensions__Take a look at the matrix below. Since there are 2 rows and 2 columns, we can call this a 2 x 2 matrix.

A matrix can be added or subtracted from a matrix of the same size. Take matrix A and matrix B below. Since matrix A and B are 2 x 2 matrices, we can add and subtract these matrices.

Let’s first try to add the matrices.

We first add the numbers from the first row and first column:

Then, we add the numbers from the first row and second column:

Next, we add the numbers from the second row and first column:

We finally add the numbers from the second row and second column:

Now, let’s try to subtract the matrices from each other.

Follow the same steps as above with addition. Did you get the same answer as shown below?