The CAS Registry Mumber 776995-24-5 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 7,7,6,9,9 and 5 respectively; the second part has 2 digits, 2 and 4 respectively. Calculate Digit Verification of CAS Registry Number 776995-24: (8*7)+(7*7)+(6*6)+(5*9)+(4*9)+(3*5)+(2*2)+(1*4)=245 245 % 10 = 5 So 776995-24-5 is a valid CAS Registry Number.