The CAS Registry Mumber 93741-50-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,3,7,4 and 1 respectively; the second part has 2 digits, 5 and 0 respectively. Calculate Digit Verification of CAS Registry Number 93741-50: (7*9)+(6*3)+(5*7)+(4*4)+(3*1)+(2*5)+(1*0)=145 145 % 10 = 5 So 93741-50-5 is a valid CAS Registry Number.