If you know the names of your sheets, you can create a cell array containing those names. The output from the xlsread function will contain only the numeric data from the spreadsheet, and it is read into a cell in the variable data. I also created a variable named sums that contains the sum of all the data.
filename = 'Book1.xlsx';
sheetnames = { 'SheetA','SheetB','SheetC' };
n = length(sheetnames);
data = cell(n,1);
sums = zeros(n,1);
for idx = 1:n
data{idx} = xlsread(filename,sheetnames{idx});
sums(idx) = sum(data{idx}(:));
end
