A matrix is an array of numbers, symbols, or expressions that are displayed in rows and columns. The dimension of a matrix are written as r x n, where r is the number of rows and n is the number of columns. One thing you can do with matrices is add or subtract them together. The only caveat to adding or subtracting matrices is that the matrices must be the same size, i.e. must have the same dimension.

Adding and subtracting matrices is simple. Simply, add or subtract each element in the matching position, creating a new matrix with the same dimension. Let’s visualize this to get a better understanding.

Here is how to add matrices together:

You’d follow the same method for subtraction.

Here is an example of matrices that can’t be added together because they aren’t the same size:

You can see one matrix is 2x2 and the other is 2x3.

Let’s see some examples to better understand.

Here’s the first example (

click here):

1.

Add elements in the matching positions

2. Simplify

Next example (

click here):

1.

Add elements in the matching positions

2.

Simplify

Last example (

click here):

1.

Add elements in the matching positions

2.

Simplify

As you can see, adding and subtracting matrices is pretty simple. If you are interested in practicing more problems on this topic or want more help on this topic, check out Symbolab’s

Practice.

Until next time,

Leah