The CAS Registry Mumber 157960-74-2 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,5,7,9,6 and 0 respectively; the second part has 2 digits, 7 and 4 respectively. Calculate Digit Verification of CAS Registry Number 157960-74: (8*1)+(7*5)+(6*7)+(5*9)+(4*6)+(3*0)+(2*7)+(1*4)=172 172 % 10 = 2 So 157960-74-2 is a valid CAS Registry Number.