The CAS Registry Mumber 196928-53-7 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,9,6,9,2 and 8 respectively; the second part has 2 digits, 5 and 3 respectively. Calculate Digit Verification of CAS Registry Number 196928-53: (8*1)+(7*9)+(6*6)+(5*9)+(4*2)+(3*8)+(2*5)+(1*3)=197 197 % 10 = 7 So 196928-53-7 is a valid CAS Registry Number.