The CAS Registry Mumber 157006-71-8 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,5,7,0,0 and 6 respectively; the second part has 2 digits, 7 and 1 respectively. Calculate Digit Verification of CAS Registry Number 157006-71: (8*1)+(7*5)+(6*7)+(5*0)+(4*0)+(3*6)+(2*7)+(1*1)=118 118 % 10 = 8 So 157006-71-8 is a valid CAS Registry Number.