Operasi penjumlahan dan pengurangan pada matriks hanya dapat dilakukan pada matriks-matriks yang berukuran sama.
$$\color{blue}\begin{bmatrix}a_{11} & a_{12} \\a_{21} & a_{22} \end{bmatrix} + \color{blue}\begin{bmatrix}b_{11} & b_{12} \\b_{21} & b_{22} \end{bmatrix} = \color{blue}\begin{bmatrix}a_{11} + b_{11} & a_{12} + b_{12} \\a_{21} + b_{21} & a_{22} + b_{22}\end{bmatrix}$$
$$\color{blue}\begin{bmatrix}a_{11} & a_{12} \\a_{21} & a_{22} \end{bmatrix} \:-\: \color{blue}\begin{bmatrix}b_{11} & b_{12} \\b_{21} & b_{22} \end{bmatrix} = \color{blue}\begin{bmatrix}a_{11} \:-\: b_{11} & a_{12} \:-\: b_{12} \\a_{21} \:-\: b_{21} & a_{22} \:-\: b_{22}\end{bmatrix}$$