The CAS Registry Mumber 125422-39-1 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,2,5,4,2 and 2 respectively; the second part has 2 digits, 3 and 9 respectively. Calculate Digit Verification of CAS Registry Number 125422-39: (8*1)+(7*2)+(6*5)+(5*4)+(4*2)+(3*2)+(2*3)+(1*9)=101 101 % 10 = 1 So 125422-39-1 is a valid CAS Registry Number.