The CAS Registry Mumber 357174-85-7 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 3,5,7,1,7 and 4 respectively; the second part has 2 digits, 8 and 5 respectively. Calculate Digit Verification of CAS Registry Number 357174-85: (8*3)+(7*5)+(6*7)+(5*1)+(4*7)+(3*4)+(2*8)+(1*5)=167 167 % 10 = 7 So 357174-85-7 is a valid CAS Registry Number.