Explanation

Matrices can be added or subtracted only if they have the same dimensions.

Addition:
[ a b ] + [ c d ] = [ a+c b+d ]

Subtraction:
[ a b ] − [ c d ] = [ a−c b−d ]

You add or subtract corresponding entries.

Quiz

1. When can matrices be added?

2. Add [1 2] + [3 4].

3. Subtract [5 1] − [2 6].

4. Do dimensions change?

5. Can a 2×2 and 2×3 matrix be added?

Answer Key

1. Same dimensions

2. [4 6]

3. [3 −5]

4. No

5. No