The CAS Registry Mumber 125649-92-5 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,2,5,6,4 and 9 respectively; the second part has 2 digits, 9 and 2 respectively. Calculate Digit Verification of CAS Registry Number 125649-92: (8*1)+(7*2)+(6*5)+(5*6)+(4*4)+(3*9)+(2*9)+(1*2)=145 145 % 10 = 5 So 125649-92-5 is a valid CAS Registry Number.