The question is find the sum of the first 15 multiples of 8

The question is find the sum of the first 15 multiples of 8 (a.p of 10th std). my doubt is that why can’t we take 0 as a multiple of 8 so if that is the first term will be 0 and when I solve it I don’t get the answer to write because they have taken the first multiple as 8, not 0 .but why?