The CAS Registry Mumber 149720-08-1 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,4,9,7,2 and 0 respectively; the second part has 2 digits, 0 and 8 respectively. Calculate Digit Verification of CAS Registry Number 149720-08: (8*1)+(7*4)+(6*9)+(5*7)+(4*2)+(3*0)+(2*0)+(1*8)=141 141 % 10 = 1 So 149720-08-1 is a valid CAS Registry Number.