#### Answer

dimension

#### Work Step by Step

See definition: SUM, DIFFERENCE, AND SCALAR PRODUCT OF MATRICES
Let $A=\left[a_{i}\right]$ and $B=\left[b_{ij}\right]$ be $\boxed{\text{matrices of the same dimension } } m\times n,$ ...
1. The sum $A+B$ is the $m\times n$ matrix obtained by adding corresponding entries of $A$ and $B$ .
$A+B=\left[a_{ij}+b_{ij}\right]$...