The CAS Registry Mumber 100763-64-2 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,0,7,6 and 3 respectively; the second part has 2 digits, 6 and 4 respectively. Calculate Digit Verification of CAS Registry Number 100763-64: (8*1)+(7*0)+(6*0)+(5*7)+(4*6)+(3*3)+(2*6)+(1*4)=92 92 % 10 = 2 So 100763-64-2 is a valid CAS Registry Number.