The CAS Registry Mumber 30835-59-7 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 3,0,8,3 and 5 respectively; the second part has 2 digits, 5 and 9 respectively. Calculate Digit Verification of CAS Registry Number 30835-59: (7*3)+(6*0)+(5*8)+(4*3)+(3*5)+(2*5)+(1*9)=107 107 % 10 = 7 So 30835-59-7 is a valid CAS Registry Number.