The CAS Registry Mumber 153037-07-1 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,5,3,0,3 and 7 respectively; the second part has 2 digits, 0 and 7 respectively. Calculate Digit Verification of CAS Registry Number 153037-07: (8*1)+(7*5)+(6*3)+(5*0)+(4*3)+(3*7)+(2*0)+(1*7)=101 101 % 10 = 1 So 153037-07-1 is a valid CAS Registry Number.