The CAS Registry Mumber 74352-40-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,4,3,5 and 2 respectively; the second part has 2 digits, 4 and 0 respectively. Calculate Digit Verification of CAS Registry Number 74352-40: (7*7)+(6*4)+(5*3)+(4*5)+(3*2)+(2*4)+(1*0)=122 122 % 10 = 2 So 74352-40-2 is a valid CAS Registry Number.