The CAS Registry Mumber 125877-73-8 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,2,5,8,7 and 7 respectively; the second part has 2 digits, 7 and 3 respectively. Calculate Digit Verification of CAS Registry Number 125877-73: (8*1)+(7*2)+(6*5)+(5*8)+(4*7)+(3*7)+(2*7)+(1*3)=158 158 % 10 = 8 So 125877-73-8 is a valid CAS Registry Number.