The CAS Registry Mumber 79015-61-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,9,0,1 and 5 respectively; the second part has 2 digits, 6 and 1 respectively. Calculate Digit Verification of CAS Registry Number 79015-61: (7*7)+(6*9)+(5*0)+(4*1)+(3*5)+(2*6)+(1*1)=135 135 % 10 = 5 So 79015-61-5 is a valid CAS Registry Number.