Can provide demo before you decide to award.
Please allow me to do it. Will ensure everything is as per your requirement. Please do not hesitate to contact me if you have any questions. I look forward to working with you.
I can see that you're looking for a developer to build a Calculator. don't worry.. I can build this easily as I've the previous experience. I can deliver the project within few hours.
I'm waiting for your response.
Thanks