The CAS Registry Mumber 134052-00-9 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,3,4,0,5 and 2 respectively; the second part has 2 digits, 0 and 0 respectively. Calculate Digit Verification of CAS Registry Number 134052-00: (8*1)+(7*3)+(6*4)+(5*0)+(4*5)+(3*2)+(2*0)+(1*0)=79 79 % 10 = 9 So 134052-00-9 is a valid CAS Registry Number.