# How to Add and Subtract Matrices

Adding and subtracting matrices is as easy as adding and subtracting "ordinary" numbers.

## Steps

- 1
**Ensure that your matrices are usable.**To add or subtract matrices each matrix must be the same size as every other matrix. - 2
**(For subtraction only) multiply the matrix/matrices you are subtracting by -1 (invert the sign in front of each number)** - 3
**Write out the sums.**Each number on a matrix corresponds to the number(s) in the same position on every other matrix you are adding/subtracting. With simple matrices it is not usually necessary to write out the sums, but with complex matrices or large numbers of them to add together this step can help avoid simple mistakes. - 4
**Add the numbers.**This should result in a matrix the same size as each of your original matrices.

## Article Info

Categories: Algebra