The CAS Registry Mumber 131572-82-2 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,3,1,5,7 and 2 respectively; the second part has 2 digits, 8 and 2 respectively. Calculate Digit Verification of CAS Registry Number 131572-82: (8*1)+(7*3)+(6*1)+(5*5)+(4*7)+(3*2)+(2*8)+(1*2)=112 112 % 10 = 2 So 131572-82-2 is a valid CAS Registry Number.