The CAS Registry Mumber 137057-03-5 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,3,7,0,5 and 7 respectively; the second part has 2 digits, 0 and 3 respectively. Calculate Digit Verification of CAS Registry Number 137057-03: (8*1)+(7*3)+(6*7)+(5*0)+(4*5)+(3*7)+(2*0)+(1*3)=115 115 % 10 = 5 So 137057-03-5 is a valid CAS Registry Number.