The CAS Registry Mumber 1008647-74-2 includes 10 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 7 digits, 1,0,0,8,6,4 and 7 respectively; the second part has 2 digits, 7 and 4 respectively. Calculate Digit Verification of CAS Registry Number 1008647-74: (9*1)+(8*0)+(7*0)+(6*8)+(5*6)+(4*4)+(3*7)+(2*7)+(1*4)=142 142 % 10 = 2 So 1008647-74-2 is a valid CAS Registry Number.