Gina - the inputdlg function returns a cell array, so you will have to convert this into the appropriate format before trying to manipulate the data. For example,
response = inputdlg(prompt,dlg_title,num_lines,def);
data = str2num(char(response));
We convert the cell array to a string using char and then the string of characters to a numeric array using str2num. (Note that how we convert on response and not the default values of def as in your example.)
Now that you have an array of numbers, you will need to iterate over each one and determine if it is odd or even. If the former, then add it to your odd sum. And if the latter, then multiply it against your even product. You won't be able to use sum or product because you won't know the order of the odd or even numbers for every possible input. (For your example, you do know that every other number is odd or even.)
Start with the above and use a for loop to iterate over the data.
