The CAS Registry Mumber 147425-87-4 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,4,7,4,2 and 5 respectively; the second part has 2 digits, 8 and 7 respectively. Calculate Digit Verification of CAS Registry Number 147425-87: (8*1)+(7*4)+(6*7)+(5*4)+(4*2)+(3*5)+(2*8)+(1*7)=144 144 % 10 = 4 So 147425-87-4 is a valid CAS Registry Number.