The CAS Registry Mumber 78016-53-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,8,0,1 and 6 respectively; the second part has 2 digits, 5 and 3 respectively. Calculate Digit Verification of CAS Registry Number 78016-53: (7*7)+(6*8)+(5*0)+(4*1)+(3*6)+(2*5)+(1*3)=132 132 % 10 = 2 So 78016-53-2 is a valid CAS Registry Number.