The CAS Registry Mumber 79887-30-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,9,8,8 and 7 respectively; the second part has 2 digits, 3 and 0 respectively. Calculate Digit Verification of CAS Registry Number 79887-30: (7*7)+(6*9)+(5*8)+(4*8)+(3*7)+(2*3)+(1*0)=202 202 % 10 = 2 So 79887-30-2 is a valid CAS Registry Number.