The CAS Registry Mumber 77625-45-7 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,7,6,2 and 5 respectively; the second part has 2 digits, 4 and 5 respectively. Calculate Digit Verification of CAS Registry Number 77625-45: (7*7)+(6*7)+(5*6)+(4*2)+(3*5)+(2*4)+(1*5)=157 157 % 10 = 7 So 77625-45-7 is a valid CAS Registry Number.