The CAS Registry Mumber 79250-77-4 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,9,2,5 and 0 respectively; the second part has 2 digits, 7 and 7 respectively. Calculate Digit Verification of CAS Registry Number 79250-77: (7*7)+(6*9)+(5*2)+(4*5)+(3*0)+(2*7)+(1*7)=154 154 % 10 = 4 So 79250-77-4 is a valid CAS Registry Number.