The CAS Registry Mumber 7032-23-7 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 7,0,3 and 2 respectively; the second part has 2 digits, 2 and 3 respectively. Calculate Digit Verification of CAS Registry Number 7032-23: (6*7)+(5*0)+(4*3)+(3*2)+(2*2)+(1*3)=67 67 % 10 = 7 So 7032-23-7 is a valid CAS Registry Number.