The CAS Registry Mumber 126919-79-7 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,2,6,9,1 and 9 respectively; the second part has 2 digits, 7 and 9 respectively. Calculate Digit Verification of CAS Registry Number 126919-79: (8*1)+(7*2)+(6*6)+(5*9)+(4*1)+(3*9)+(2*7)+(1*9)=157 157 % 10 = 7 So 126919-79-7 is a valid CAS Registry Number.