The CAS Registry Mumber 90476-40-7 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,0,4,7 and 6 respectively; the second part has 2 digits, 4 and 0 respectively. Calculate Digit Verification of CAS Registry Number 90476-40: (7*9)+(6*0)+(5*4)+(4*7)+(3*6)+(2*4)+(1*0)=137 137 % 10 = 7 So 90476-40-7 is a valid CAS Registry Number.