The CAS Registry Mumber 125422-40-4 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, 4 and 0 respectively. Calculate Digit Verification of CAS Registry Number 125422-40: (8*1)+(7*2)+(6*5)+(5*4)+(4*2)+(3*2)+(2*4)+(1*0)=94 94 % 10 = 4 So 125422-40-4 is a valid CAS Registry Number.