Specific row and column addition for a NxM matrix

I am trying to add and subtract specfici rows and colums, the sum function is not working working for me; it is either suming up all of the values or adding all columns only.

1.1125 2.0641 2.3183 1.8751 1.2631 0.6625

3.4084 5.1874 5.2771 3.6026 2.1510 1.0079 1.) I am trying to sum up all the outside elements starting from

10.000 10.000 10.000 5.1074 2.7302 1.2181 3.4084 and ending at 2.8216

5.3388 6.2794 6.0136 4.0968 2.4445 1.1343 2.) As well as these 3 elements going in the inside starting from

2.9655 3.7652 3.6784 2.8216 1.8166 0.8745 10.000 and ending at 3.6784

1.6518 2.1375 2.1130 1.6946 1.1259 0.5472

0.8781 1.0199 0.9417 0.7178 0.4451 0.1884 4.) then subtract the outter from inner with the abs function

0.4931 0.6300 0.6188 0.5039 0.3377 0.1618

0.2869 0.3881 0.3997 0.3411 0.2401 0.1213

0.1692 0.2358 0.2506 0.2208 0.1603 0.0832

0.0971 0.1354 0.1462 0.1313 0.0971 0.0511

0.0472 0.0625 0.0674 0.0611 0.0456 0.0242

Answer 1

[Scott MacKenzie]

% assume the data are in z
outLogical = z > 3.4084 & z < 2.8216;
inLogical = z < 10.000 & z > 3.6874;
sumOuter = sum(z(outLogical));
sumInner = sum(z(inLogical));
result = abs(sumInner - sumOuter);