The CAS Registry Mumber 142907-00-4 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,4,2,9,0 and 7 respectively; the second part has 2 digits, 0 and 0 respectively. Calculate Digit Verification of CAS Registry Number 142907-00: (8*1)+(7*4)+(6*2)+(5*9)+(4*0)+(3*7)+(2*0)+(1*0)=114 114 % 10 = 4 So 142907-00-4 is a valid CAS Registry Number.