The CAS Registry Mumber 157006-72-9 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 2 respectively. Calculate Digit Verification of CAS Registry Number 157006-72: (8*1)+(7*5)+(6*7)+(5*0)+(4*0)+(3*6)+(2*7)+(1*2)=119 119 % 10 = 9 So 157006-72-9 is a valid CAS Registry Number.