The CAS Registry Mumber 3827-76-7 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 3,8,2 and 7 respectively; the second part has 2 digits, 7 and 6 respectively. Calculate Digit Verification of CAS Registry Number 3827-76: (6*3)+(5*8)+(4*2)+(3*7)+(2*7)+(1*6)=107 107 % 10 = 7 So 3827-76-7 is a valid CAS Registry Number.