The CAS Registry Mumber 101481-81-6 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,1,4,8 and 1 respectively; the second part has 2 digits, 8 and 1 respectively. Calculate Digit Verification of CAS Registry Number 101481-81: (8*1)+(7*0)+(6*1)+(5*4)+(4*8)+(3*1)+(2*8)+(1*1)=86 86 % 10 = 6 So 101481-81-6 is a valid CAS Registry Number.