The CAS Registry Mumber 82855-10-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,2,8,5 and 5 respectively; the second part has 2 digits, 1 and 0 respectively. Calculate Digit Verification of CAS Registry Number 82855-10: (7*8)+(6*2)+(5*8)+(4*5)+(3*5)+(2*1)+(1*0)=145 145 % 10 = 5 So 82855-10-5 is a valid CAS Registry Number.