Anyone Know if there is a fast way to extract number from all numer matrix?

[Assassinatemax]

Here is what I enter:
[1 2
3 4](1,1) and the error: Syntax Error raised.

I can extract the value normally from this matrix:
[1 2
a 4](1,1) where a is a variable.

I am pretty sure this is caused by how calculator treat the matrix.