I have this problem i can't seem to figure out,i'll do my best to explain it here.

I have a series of checkboxes each one having a name and a value and a person can choose either one or all of the boxes(it can't be radiobuttons because you can only make a single choice)
I want to know if it is possible to calculate the total amount if the person chooses any number of checkboxes from one to eight.
I.e checkbox1 value = 5
checkbox2 value = 15
checkbox3 value = 7.

I would apprieciate any kind of help here thanks