Are you saying that you want to see the math result while you are filling the form, or after you submitted the form?
If it’s inside of the form while you are filling in the data, then the math columns won’t work or show as an option because nothing has been written to the table until you click on submit. Instead you would have to ignore the glide form and instead create a custom form. How do I create a custom form?
If instead you want to see the math result on the detail screen after you submit the form, then have you tried adding components to display that those math column values?