The CAS Registry Mumber 35923-42-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 3,5,9,2 and 3 respectively; the second part has 2 digits, 4 and 2 respectively. Calculate Digit Verification of CAS Registry Number 35923-42: (7*3)+(6*5)+(5*9)+(4*2)+(3*3)+(2*4)+(1*2)=123 123 % 10 = 3 So 35923-42-3 is a valid CAS Registry Number.