The CAS Registry Mumber 125879-76-7 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 9 respectively; the second part has 2 digits, 7 and 6 respectively. Calculate Digit Verification of CAS Registry Number 125879-76: (8*1)+(7*2)+(6*5)+(5*8)+(4*7)+(3*9)+(2*7)+(1*6)=167 167 % 10 = 7 So 125879-76-7 is a valid CAS Registry Number.