The CAS Registry Mumber 928621-15-2 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 9,2,8,6,2 and 1 respectively; the second part has 2 digits, 1 and 5 respectively. Calculate Digit Verification of CAS Registry Number 928621-15: (8*9)+(7*2)+(6*8)+(5*6)+(4*2)+(3*1)+(2*1)+(1*5)=182 182 % 10 = 2 So 928621-15-2 is a valid CAS Registry Number.