MATLAB: Add two elements from diffrent matrices and store it into new matrix.

Question

my code is like this and i got error:

Index exceeds array bounds.
Error in line 3
    QtA(t)=max(0,QtA(t-1)+LAMtA(t)-OtA(t)-LtA(t));

i just want to do arithmatic operation of diffrent elemtents of diffrent matrices and want to store it into a matrix as element. please help me. I am new at matlab.

i have matrices as shown in fig.

 VtA(t)=max(0,N1-LAMtA(t-1)-LAMtA(t)+OtA(t));
    VtD(t)=max(0,N2-LAMtD(t-1)-LAMtD(t)+OtD(t));
    QtA(t)=max(0,QtA(tp-1)+LAMtA(t)-OtA(t)-LtA(t));
    QtD(t)=max(0,QtD(tp-1)+LAMtD(t)-OtD(t)-LtD(t));

Answer 1

    QtA(t)=max(0,QtA(tp)+LAMtA(t)-OtA(t)-LtA(t-1));