The CAS Registry Mumber 306279-65-2 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 3,0,6,2,7 and 9 respectively; the second part has 2 digits, 6 and 5 respectively. Calculate Digit Verification of CAS Registry Number 306279-65: (8*3)+(7*0)+(6*6)+(5*2)+(4*7)+(3*9)+(2*6)+(1*5)=142 142 % 10 = 2 So 306279-65-2 is a valid CAS Registry Number.