The CAS Registry Mumber 36142-84-4 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 3,6,1,4 and 2 respectively; the second part has 2 digits, 8 and 4 respectively. Calculate Digit Verification of CAS Registry Number 36142-84: (7*3)+(6*6)+(5*1)+(4*4)+(3*2)+(2*8)+(1*4)=104 104 % 10 = 4 So 36142-84-4 is a valid CAS Registry Number.