Adding, Subtracting, and Matrices, Oh My! It's simple to add and subtract matrices, but they must always be the same size for it to work . The answers are always the same size too. Check it out:

All you do is add the entries in each corresponding place:

Subtraction? Same idea.

Now we just subtract the entries in each place:

Looks tough, but as long as you don't lose your place, you're golden. But remember, they must be the same size. And a 2 × 3 is not the same as a 3 × 2, for example.

Practice:

Example 1

These matrices are the same size so these can be added. We just add the entries in each corresponding place:

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Example 2

These matrices are the same size so these can be added. We just add the entries in each corresponding place:

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Example 3

These matrices are not the same size. They cannot be added.

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Example 4

These matrices are the same size so these can be subtracted. We just subtract the entries in each corresponding place:

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Example 5

These matrices are the same size so these can be subtracted. We just subtract the entries in each corresponding place:

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Example 6

These matrices are not the same size. They cannot be subtracted.

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Example 1
Add these matrices or, if not possible, explain why:

Gimme a Hint
Hint

matrices must be the same size to add

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Example 2
Add these matrices or, if not possible, explain why:

Gimme a Hint
Hint

matrices must be the same size to add

Show Answer Answer

These are different sizes so they cannot be added.

Example 3
Subtract these matrices, or, if not possible, explain why.

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Answer

Example 4
Subtract these matrices, or, if not possible, explain why.

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Answer

Example 5
Subtract these matrices, or, if not possible, explain why.

Show Answer

Answer

These matrices are not the same size so they cannot be subtracted.