If A is order `mxxn` and B is also of order `mxxn` then `(A+B)` is a matrix of order ___________.

Answer

To solve the problem, we need to determine the order of the matrix resulting from the addition of two matrices A and B, both of which have the same order.

### Step-by-Step Solution:

1. **Identify the Order of Matrices A and B**:
- We are given that matrix A has an order of \( m \times n \) (which means it has m rows and n columns).
- Similarly, matrix B also has an order of \( m \times n \).

2. **Understand Matrix Addition**:
- When adding two matrices, the operation is only defined if both matrices have the same order. This means that both matrices must have the same number of rows and the same number of columns.

3. **Add the Matrices**:
- Since both A and B have the same order \( m \times n \), we can add them together. The addition is performed by adding corresponding elements from each matrix.

4. **Determine the Order of the Resultant Matrix**:
- The resultant matrix, which is the sum of A and B, will also have the same order as the original matrices. Therefore, the order of the resultant matrix \( (A + B) \) will also be \( m \times n \).

5. **Conclusion**:
- Thus, we conclude that if A is of order \( m \times n \) and B is also of order \( m \times n \), then the order of the matrix \( (A + B) \) is also \( m \times n \).

### Final Answer:
The order of the matrix \( (A + B) \) is \( m \times n \).

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