Adding of matrix operation. between rectangles

The problem is putting the random numbers in between the square in the rectangles and adding them. You can look at the desired output. I already have the code for the rectangle which using length and with. I'll just convert it to column and rows. But the problem is putting the random numbers between .

    int len, wid;


    String sep = "+---";
    String w_block = "|   ";

    for(int i = 0; i < wid; i++)
    {
        for(int j = 0; j < len; j++)
        {
            out.print(sep);
        }
        out.print("+\n");

        for(int k = 0; k < len; k++)
        {
            out.print(w_block);
        }
        out.print("|\n");
    }

    for(int j = 0; j < len; j++)
    {
        out.print(sep);
    }
    out.print("+");  

I expect the output to be like this