The CAS Registry Mumber 113827-75-1 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,1,3,8,2 and 7 respectively; the second part has 2 digits, 7 and 5 respectively. Calculate Digit Verification of CAS Registry Number 113827-75: (8*1)+(7*1)+(6*3)+(5*8)+(4*2)+(3*7)+(2*7)+(1*5)=121 121 % 10 = 1 So 113827-75-1 is a valid CAS Registry Number.