The CAS Registry Mumber 77536-64-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,7,5,3 and 6 respectively; the second part has 2 digits, 6 and 4 respectively. Calculate Digit Verification of CAS Registry Number 77536-64: (7*7)+(6*7)+(5*5)+(4*3)+(3*6)+(2*6)+(1*4)=162 162 % 10 = 2 So 77536-64-2 is a valid CAS Registry Number.