Hello... is my math right? If a dealer wants to know face value for 90% junk silver he multiplies .715x spot right. If spot is $17.50 x .715 = $12.51 What am i doing wrong to find value for 1 silver quarter?

Divide $12.51 by 4! A good resource is the website coinflation.com. They calculate and do the math for you. They use .7234 vs .715 so just be aware.