The CAS Registry Mumber 142790-00-9 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,4,2,7,9 and 0 respectively; the second part has 2 digits, 0 and 0 respectively. Calculate Digit Verification of CAS Registry Number 142790-00: (8*1)+(7*4)+(6*2)+(5*7)+(4*9)+(3*0)+(2*0)+(1*0)=119 119 % 10 = 9 So 142790-00-9 is a valid CAS Registry Number.