The CAS Registry Mumber 62156-07-4 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 6,2,1,5 and 6 respectively; the second part has 2 digits, 0 and 7 respectively. Calculate Digit Verification of CAS Registry Number 62156-07: (7*6)+(6*2)+(5*1)+(4*5)+(3*6)+(2*0)+(1*7)=104 104 % 10 = 4 So 62156-07-4 is a valid CAS Registry Number.