The CAS Registry Mumber 50336-49-7 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,0,3,3 and 6 respectively; the second part has 2 digits, 4 and 9 respectively. Calculate Digit Verification of CAS Registry Number 50336-49: (7*5)+(6*0)+(5*3)+(4*3)+(3*6)+(2*4)+(1*9)=97 97 % 10 = 7 So 50336-49-7 is a valid CAS Registry Number.