how do I create button that when I click on it produces the math problems that I have below. I know how to create button with links but the functions...

how do I create button that when I click on it produces the math problems that I have below. I know how to create  button with links but the functions I'm still learning. I have most of this done I was trying to upload my file but I'm getting a error message

Create alert the adds 5+7 and notifies the webpage user.