The CAS Registry Mumber 146-40-7 includes 6 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 3 digits, 1,4 and 6 respectively; the second part has 2 digits, 4 and 0 respectively. Calculate Digit Verification of CAS Registry Number 146-40: (5*1)+(4*4)+(3*6)+(2*4)+(1*0)=47 47 % 10 = 7 So 146-40-7 is a valid CAS Registry Number.