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Matrix Addition Calculator

Add or subtract two 3x3 matrices. Type into the grids and the result updates live.

Matrix Addition

Fill both 3x3 grids. Results update live.

Result
A + B

Edit the grids to compute.

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Rule: add or subtract matching entries: C[i][j] = A[i][j] +/- B[i][j]. Both matrices must have the same size.
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Entry by entry

Matrix addition pairs up entries in the same position: the top-left of A combines with the top-left of B, and so on through all nine cells. Subtraction works the same way with minus signs. The two matrices must be the same size or the operation is undefined.

Commutative and simple

Unlike multiplication, matrix addition is commutative: A + B always equals B + A. It is the gentlest matrix operation, and it is the foundation for everything from image blending to solving linear systems.

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Matrix Addition FAQs

What is the sum of [[1,2,3],[4,5,6],[7,8,9]] and [[9,8,7],[6,5,4],[3,2,1]]?
Add matching entries: [[10,10,10],[10,10,10],[10,10,10]]. These are the preloaded grids, so you see the answer immediately.
Can I subtract matrices too?
Yes. Switch the Operation dropdown to A - B and the result grid updates live to show the difference.
Can I add a 2x3 and a 3x3 matrix?
No. Addition requires identical dimensions, entry positions must line up one to one. Use matching sizes only.
Is matrix addition commutative?
Yes: A + B = B + A always holds. That is not true of matrix multiplication, which is why the order matters there.
Does the tool send my matrices anywhere?
No. Every entry is computed in your browser; nothing leaves your device.
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