The CAS Registry Mumber 115982-57-5 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,1,5,9,8 and 2 respectively; the second part has 2 digits, 5 and 7 respectively. Calculate Digit Verification of CAS Registry Number 115982-57: (8*1)+(7*1)+(6*5)+(5*9)+(4*8)+(3*2)+(2*5)+(1*7)=145 145 % 10 = 5 So 115982-57-5 is a valid CAS Registry Number.