The CAS Registry Mumber 76519-45-4 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,6,5,1 and 9 respectively; the second part has 2 digits, 4 and 5 respectively. Calculate Digit Verification of CAS Registry Number 76519-45: (7*7)+(6*6)+(5*5)+(4*1)+(3*9)+(2*4)+(1*5)=154 154 % 10 = 4 So 76519-45-4 is a valid CAS Registry Number.