The CAS Registry Mumber 1309962-79-5 includes 10 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 7 digits, 1,3,0,9,9,6 and 2 respectively; the second part has 2 digits, 7 and 9 respectively. Calculate Digit Verification of CAS Registry Number 1309962-79: (9*1)+(8*3)+(7*0)+(6*9)+(5*9)+(4*6)+(3*2)+(2*7)+(1*9)=185 185 % 10 = 5 So 1309962-79-5 is a valid CAS Registry Number.