The CAS Registry Mumber 138572-07-3 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,3,8,5,7 and 2 respectively; the second part has 2 digits, 0 and 7 respectively. Calculate Digit Verification of CAS Registry Number 138572-07: (8*1)+(7*3)+(6*8)+(5*5)+(4*7)+(3*2)+(2*0)+(1*7)=143 143 % 10 = 3 So 138572-07-3 is a valid CAS Registry Number.