The CAS Registry Mumber 265310-79-0 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 2,6,5,3,1 and 0 respectively; the second part has 2 digits, 7 and 9 respectively. Calculate Digit Verification of CAS Registry Number 265310-79: (8*2)+(7*6)+(6*5)+(5*3)+(4*1)+(3*0)+(2*7)+(1*9)=130 130 % 10 = 0 So 265310-79-0 is a valid CAS Registry Number.