Matrix Addition Calculator

Published on: September 7 2025
Final Answer: Free Full Steps: Pro

This Matrix Addition Calculator helps you add two matrices and shows each step clearly. It works by adding the corresponding entries from matrices of the same dimensions to form a new matrix. This makes it useful for checking answers, understanding how matrix addition works, and practising linear algebra step by step.

Step-by-step method

  1. Check that both matrices have the same number of rows and columns.
  2. Add entries in the same position, such as row 1 column 1 with row 1 column 1.
  3. Write each sum in the matching position of the result matrix.

Formula:

\(\text{If } A = [a_{ij}] \text{ and } B = [b_{ij}]\text{, then } A + B = [a_{ij} + b_{ij}]\)

Example 1: Take the matrices below.

\(\begin{pmatrix} 12 & -3 \\ 40 & 7 \end{pmatrix} + \begin{pmatrix} 5 & 18 \\ -9 & 2 \end{pmatrix}\)

Step 1 - Check that both matrices have the same number of rows and columns.

In this problem: Matrix A and Matrix B are both \(2 \times 2\), so they can be added.

\(\begin{pmatrix} 12 & -3 \\ 40 & 7 \end{pmatrix} + \begin{pmatrix} 5 & 18 \\ -9 & 2 \end{pmatrix}\)

Step 2 - Add entries in the same position, such as row 1 column 1 with row 1 column 1.

In this problem: Each entry is paired with the entry in the same row and column.

\(\begin{pmatrix} 12 + 5 & -3 + 18 \\ 40 + (-9) & 7 + 2 \end{pmatrix}\)

Step 3 - Write each sum in the matching position of the result matrix.

In this problem: Each sum is placed back into the same position in the answer matrix.

\(\begin{pmatrix} 12 + 5 = 17 & -3 + 18 = 15 \\ 40 + (-9) = 31 & 7 + 2 = 9 \end{pmatrix} = \begin{pmatrix} 17 & 15 \\ 31 & 9 \end{pmatrix}\)

Final answer:

\(A + B = \begin{pmatrix} 17 & 15 \\ 31 & 9 \end{pmatrix}\)

Example 2: Take the matrices below.

\(\begin{pmatrix} 1000 & -2 & 33 \\ 4 & 15 & 6 \\ 7 & 8 & 9 \end{pmatrix} + \begin{pmatrix} 1 & 2 & 30 \\ 4 & 5 & 6 \\ -7 & 0 & 11 \end{pmatrix}\)

Step 1 - Check that both matrices have the same number of rows and columns.

In this problem: Matrix A and Matrix B are both \(3 \times 3\), so they can be added.

\(\begin{pmatrix} 1000 & -2 & 33 \\ 4 & 15 & 6 \\ 7 & 8 & 9 \end{pmatrix} + \begin{pmatrix} 1 & 2 & 30 \\ 4 & 5 & 6 \\ -7 & 0 & 11 \end{pmatrix}\)

Step 2 - Add entries in the same position, such as row 1 column 1 with row 1 column 1.

In this problem: Each entry is paired with the entry in the same row and column.

\(\begin{pmatrix} 1000 + 1 & -2 + 2 & 33 + 30 \\ 4 + 4 & 15 + 5 & 6 + 6 \\ 7 + (-7) & 8 + 0 & 9 + 11 \end{pmatrix}\)

Step 3 - Write each sum in the matching position of the result matrix.

In this problem: Each sum is placed back into the same position in the answer matrix.

\(\begin{pmatrix} 1000 + 1 = 1001 & -2 + 2 = 0 & 33 + 30 = 63 \\ 4 + 4 = 8 & 15 + 5 = 20 & 6 + 6 = 12 \\ 7 + (-7) = 0 & 8 + 0 = 8 & 9 + 11 = 20 \end{pmatrix} = \begin{pmatrix} 1001 & 0 & 63 \\ 8 & 20 & 12 \\ 0 & 8 & 20 \end{pmatrix}\)

Final answer:

\(A + B = \begin{pmatrix} 1001 & 0 & 63 \\ 8 & 20 & 12 \\ 0 & 8 & 20 \end{pmatrix}\)
See Example 1 Hide Example 1

Problem

\(\begin{pmatrix} 12 & -3 \\ 40 & 7 \end{pmatrix} + \begin{pmatrix} 5 & 18 \\ -9 & 2 \end{pmatrix}\)

Approach

Step-by-step method

  1. Check that both matrices have the same number of rows and columns.
  2. Add entries in the same position, such as row 1 column 1 with row 1 column 1.
  3. Write each sum in the matching position of the result matrix.

Step 1

Step 1 - Check that both matrices have the same number of rows and columns.

In this problem: Matrix A and Matrix B are both \(2 \times 2\), so they can be added.

\(\begin{pmatrix} 12 & -3 \\ 40 & 7 \end{pmatrix} + \begin{pmatrix} 5 & 18 \\ -9 & 2 \end{pmatrix}\)

Step 2

Step 2 - Add entries in the same position, such as row 1 column 1 with row 1 column 1.

In this problem: Each entry is paired with the entry in the same row and column.

\(\begin{pmatrix} 12 + 5 & -3 + 18 \\ 40 + (-9) & 7 + 2 \end{pmatrix}\)

Step 3

Step 3 - Write each sum in the matching position of the result matrix.

In this problem: Each sum is placed back into the same position in the answer matrix.

\(\begin{pmatrix} 12 + 5 = 17 & -3 + 18 = 15 \\ 40 + (-9) = 31 & 7 + 2 = 9 \end{pmatrix} = \begin{pmatrix} 17 & 15 \\ 31 & 9 \end{pmatrix}\)

Final Answer

\(A + B = \begin{pmatrix} 17 & 15 \\ 31 & 9 \end{pmatrix}\)
See Example 2 Hide Example 2

Problem

\(\begin{pmatrix} 1000 & -2 & 33 \\ 4 & 15 & 6 \\ 7 & 8 & 9 \end{pmatrix} + \begin{pmatrix} 1 & 2 & 30 \\ 4 & 5 & 6 \\ -7 & 0 & 11 \end{pmatrix}\)

Approach

Step-by-step method

  1. Check that both matrices have the same number of rows and columns.
  2. Add entries in the same position, such as row 1 column 1 with row 1 column 1.
  3. Write each sum in the matching position of the result matrix.

Step 1

Step 1 - Check that both matrices have the same number of rows and columns.

In this problem: Matrix A and Matrix B are both \(3 \times 3\), so they can be added.

\(\begin{pmatrix} 1000 & -2 & 33 \\ 4 & 15 & 6 \\ 7 & 8 & 9 \end{pmatrix} + \begin{pmatrix} 1 & 2 & 30 \\ 4 & 5 & 6 \\ -7 & 0 & 11 \end{pmatrix}\)

Step 2

Step 2 - Add entries in the same position, such as row 1 column 1 with row 1 column 1.

In this problem: Each entry is paired with the entry in the same row and column.

\(\begin{pmatrix} 1000 + 1 & -2 + 2 & 33 + 30 \\ 4 + 4 & 15 + 5 & 6 + 6 \\ 7 + (-7) & 8 + 0 & 9 + 11 \end{pmatrix}\)

Step 3

Step 3 - Write each sum in the matching position of the result matrix.

In this problem: Each sum is placed back into the same position in the answer matrix.

\(\begin{pmatrix} 1000 + 1 = 1001 & -2 + 2 = 0 & 33 + 30 = 63 \\ 4 + 4 = 8 & 15 + 5 = 20 & 6 + 6 = 12 \\ 7 + (-7) = 0 & 8 + 0 = 8 & 9 + 11 = 20 \end{pmatrix} = \begin{pmatrix} 1001 & 0 & 63 \\ 8 & 20 & 12 \\ 0 & 8 & 20 \end{pmatrix}\)

Final Answer

\(A + B = \begin{pmatrix} 1001 & 0 & 63 \\ 8 & 20 & 12 \\ 0 & 8 & 20 \end{pmatrix}\)
Matrix A
+
Matrix B