The CAS Registry Mumber 124852-99-9 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,2,4,8,5 and 2 respectively; the second part has 2 digits, 9 and 9 respectively. Calculate Digit Verification of CAS Registry Number 124852-99: (8*1)+(7*2)+(6*4)+(5*8)+(4*5)+(3*2)+(2*9)+(1*9)=139 139 % 10 = 9 So 124852-99-9 is a valid CAS Registry Number.