The CAS Registry Mumber 85102-40-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,5,1,0 and 2 respectively; the second part has 2 digits, 4 and 0 respectively. Calculate Digit Verification of CAS Registry Number 85102-40: (7*8)+(6*5)+(5*1)+(4*0)+(3*2)+(2*4)+(1*0)=105 105 % 10 = 5 So 85102-40-5 is a valid CAS Registry Number.