This can be a great way to check your work or to see How to find class boundaries in excel.
Find the upper bound by adding 1.96 multiplied by this result to your mean value. So if the mean is in cell D1 and this last result is in D4, enter =D1+ (1.96 D4) into a blank cell to
Its a very good app, it does its job, if you go for a paid version you get full solution with every step explained clearly, it also gives you the option to look at the solution and you can learn from that, especially great with fractions and exponents.